18

DARNIOJI ARCHITEKTŪRA IR STATYBA
2014. No. 1(6) 

JOURNAL OF SUSTAINABLE ARCHITECTURE AND CIVIL ENGINEERING
ISSN 2029–9990

Environmental Assessment of Typical Construction Solutions in 
Residential Buildings in Greece

Dimitrios Bikas*, Panagiotis Chastas

Aristotle University of Thessaloniki, Dept. of Civil Engineering, Laboratory of Building Construction and Building 
Physics, 54124 Thessaloniki, Greece.

*Corresponding author bikasd@civil.auth.gr

  http://dx.doi.org/10.5755/j01.sace.6.1.5949

Climatic change has been one of the most important issues that occupies the scientific community around the world for 
many years now and affects economic, environmental and social policies. A continuous effort is made in order to manage 
and reduce the demand and consumption of both energy and materials, with the further goal of reducing environmental 
impacts in all sectors of the constantly developing society. One of the most important sectors that are being developed, 
following the ongoing global urbanization and population growth, striving to meet the increasing demand is the construction 
sector. For the proper management of the demand and consumption legalization has been adopted and methodologies and 
tools have been created. In the European Union such an effort is the European Community Law 2002/91/EC which appears 
in the Greek legislation by the law 3661/2008 and the Regulation of the Energy Performance of Buildings (ΚΕΝΑΚ, 
2010), aiming to upgrade the existing building stock and compliance the future construction to the new requirements 
(ΤΟΤΕΕ20701−2, 2010). This is an effort to reduce the environmental impacts from the energy consumption in the building 
sector. Another important issue is the environmental impact from the materials and the stages of the construction of the 
building.  In this scientific area efforts in Europe have been made such as the Environmental Product Declaration. A helpful 
tool for this analysis, which has not yet widely been used in Greece, is the LCA (Life Cycle Assessment), which is used to 
calculate the environmental impact throughout the life cycle of a material, a product or a process. The aim of this paper was 
to provide the ideal construction solution for the opaque elements of the building envelope of residential buildings in Greece 
and also create a database from which an engineer or a contractor, at the design stage of the building, can use to choose the 
solution with the least environmental impact depending on the climatic zone and its energy performance, according to the 
Regulation of Energy Performance in Buildings (ΚΕΝΑΚ, 2010), that is going to be constructed.

Keywords: life cycle assessment, residential buildings, energy consumption, U value, TOPSIS. 

1. Introduction

Buildings are responsible for 40 % of the energy 
consumption in the European Union. As indicated by the 
latest data of 2011 households are responsible for the 26.7 % 
of the final energy consumption in Europe (Eurostat, 2013).

Greece from the year 2007 (the entrance year into the 
economic crisis) has launched a downward trend in gross 
domestic consumption of primary energy. The same trend 
is observed at the building activity. Since 2007 when the 
building sector began with 16,910,545 of constructed square 
meters building area there is a fall in 2012 to 2,641,200 
square meters (EL.STAT., 2013). However from the year 
1997 until 2007 the building activity was very intense and a 
significant building stock was constructed. As this is one of 
the most energy intensive parts of the Greek and European 
economy there is an urgent need to reduce the energy 
consumption and environmental impacts in this sector.

An effort for energy upgrading of buildings, in line 
with the Greek legislation in 2013, is the European Directive 
of the European Parliament 2012/31/EE. Its aim is to review 
periodically the provisions on energy performance of 
buildings, such as the Regulation of the Energy Performance 
in Buildings (ΚΕΝΑΚ, 2010), with the further goal all new 
buildings until the end of 2020 and new buildings occupied 
by public authorities until 2018 to become buildings with 
nearly zero energy consumption. Even encourages the 
conversion of the existing building stock in buildings with 
nearly zero energy consumption with funded programs 
for insulation installation, replacing windows and doors, 
upgrading HVAC systems etc.

However this effort only attempts to reduce the 
environmental impact of the consumption of energy during 
the operation stage of the building. The environmental 



19

impacts from the other stages of the life cycle of the building 
are ignored as they contribute with a small percentage at the 
total environmental impact of its life cycle.

The aim of this paper is to calculate the environmental 
impact of typical construction solutions of the building 
envelope in residential buildings and for a square meter 
cross section. Furthermore its aim is to provide the ideal 
solution, by using the multi-criteria analysis TOPSIS, for 
each building element and for each climatic zone according 
to KENAK.  These results could be a helpful tool for 
a contractor or an engineer, in the design stage of a new 
building or in the design stage of an effort to upgrade the 
energy performance of the building stock, by choosing the 
ideal solution with the least environmental impact and also 
taking into account the energy performance of the building 
and the U value.

2. Methods

2.1. Typical construction solution of residential buildings in 
Greece

For this study, different construction solutions of 
building elements which constitute the building envelope of 
residential buildings in Greece were selected. 

For the construction solutions of column are considered 
a cross section of reinforced concrete 30 cm thick, 
insulating material (polyurethane, extruded polystyrene 
(XPS)  and  expanded polystyrene (EPS)) and coating with 
plaster internally 2 cm thick and lime plaster externally  
2.5 cm thick. A final covering with color is considered to the 
internal and external surface of the element. For construction 
solutions of beam and wall with reinforced concrete there 
is the same configuration as the column with the thickness 
difference of the concrete which is 25 cm and the amount 
of the reinforcing steel. As regards masonry is constructed 
with bricks of 18 cm thick (two layers of 9 cm thick), 
adhesive mortar for their connection, insulating material 
(rock wool, glass wool, extruded polystyrene (XPS) and  
expanded polystyrene (EPS)) coated with plaster internally 
2 cm thick and lime plaster 2.5 cm thick externally and final 
covering  with color in the internal and external surface. 
The variants differ in the use of an air layer, in the form 
of air gap, and its position and the mounting position of 
the insulating material. The flat roof construction solutions 
include accessible and inverted (with the insulation layer on 
the outside in order to protect the underlying layers), with 
variation in the thermal insulation material (polyurethane 
or extruded polystyrene (XPS)). Includes materials such 
as bitumen sheets, PVC sheet, HDPE sheet, reinforced 
concrete slab of 15 cm thick, gravel-concrete 8cm thick, 
lined with plaster in the internal surface 2 cm thick and 
exterior topcoat with gravel or stone slabs etc. The inclined 
roof construction includes solutions which differ in the 
use of thermal insulation material (expanded polystyrene 
(EPS) or glass wool) and the use of concrete slab of 15cm 
or wood for the case of wooden roof with ceramic tiles.  The 
construction solutions for flooring over pilotis differ in the 
type of insulation (extruded polystyrene (XPS) and glass 
wool) with an outer covering (lime plaster and cement board 
respectively). And a final covering with wood, marble or 

ceramic tiles is considered in the internal surface. The main 
layer is the reinforced concrete slab 15 cm thick.

2.2. Thickness of insulating material and U value
As observed the main difference in the cross sections 

of the construction solutions of a building element is 
located in the choice of the insulating material. For the final 
configuration of the thickness of the insulating layer the 
thermal transmittance (U value) was calculated (Eq.1).

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ext

air l

with 

d in

le 1

 (2

eme

the

hose

g to

alue

m
2

.K)

f En

lima

zone

0,3

0,4

0,3

atio

nto 

of 

reg

clim

gion

met

than

cate

d in

ern

lay

th

n th

).  

2) 

ent a

erm

en 

o th

es a

K) p

nerg

atic

e Δ

5 

40 

5 

on 

fou

eac

gion

mat

n of

ter, 

n th

ed 

n th

nal 

er 

he 

he 

as 

mal 

in 

he 

as 

er 

gy 

c 

of 

ur 

ch 

ns 

tic 

f a 

is 

he 

in 

his 

 

,   (1)

where: Rsi – thermal resistance of internal surface (m2.K/ W); 
di – layer thickness (m); λi – thermal conductivity coefficient 
(W/m.K); Rse – thermal resistance of external surface 
(m2.K/W); Ral – thermal resistance of the air layer of the air 
gap (m2.K/W).

The calculated U value was compared with the 
maximum U value per climatic zone as defined in the 
Regulation of Energy Performance of Buildings (table 1). 

t

a

2

2

G

b

r

c

t

p

c

e

c

e

r

c

i

m

l

i

p

w

t

a

l

m

c

t

u

m

I

H

g

s

s

w

(

c

w

o

p

(

c

t

c

2

o

i

c

t

 

w

W

taki

and

2. M

2.1.

Gre

buil

resi

con

thic

poly

coa

exte

con

elem

rein

colu

is 2

mas

laye

insu

poly

with

thic

and

laye

mou

con

the 

und

mat

Incl

HD

grav

surf

slab

whi

(exp

con

with

ove

poly

(lim

cov

the 

con

2.2.

of t

in 

con

ther

U =

  

whe

W)

ing 

d the

Met

. Ty

eece

F

ldin

iden

F

nsid

ck, 

ysty

ating

ern

nsid

men

nfor

umn

25 c

son

ers 

ulat

ysty

h p

ck e

d ex

er, 

unt

nstru

ins

derl

teri

lud

DPE

vel

face

bs e

ich 

pan

ncre

h c

er p

ysty

me 

verin

in

ncre

. Th

A

the 

the

nfig

rma

  

 

R

=

ere

; �

int

e U

tho

ypic

e 

For 

ng e

ntia

For 

dere

i

yren

g w

ally

dere

nt. 

rced

n w

cm 

nry 

of 

ting

yren

plas

exte

xter

in 

ting

ucti

sula

lyin

al 

des 

E sh

-co

e 2 

etc.

di

nded

ete 

cera

pilo

yren

pla

ng 

nter

ete s

hick

As o

con

e c

gura

al tr

 

siR +

:  �
�

�
�
 –

to a

U va

ods

cal 

th

elem

al bu

th

ed a

insu

ne 

with

y 2

ed 

For

d c

with

and

is 

9 c

g m

ne 

ster 

erna

rnal

th

g po

ion

atio

ng l

(po

ma

hee

oncr

cm

 Th

iffe

d p

slab

amic

otis

ne 

aster

wit

rnal

slab

knes

obs

nstr

hoi

ation

rans

+ ∑

��
 –

– la

acco

alue

con

his 

men

uild

he 

a c

ulat

(XP

h pl

2.5 

to 

r co

conc

h th

d th

con

cm 

mat

(XP

int

ally

l su

he f

osit

n so

on l

laye

olyu

ater

et, 

rete

m th

he i

er i

poly

b o

c ti

s d

(XP

r an

th w

l su

b 15

ss o

serv

ruct

ice 

n o

smi

  

1

1

n
i

i

d

 

λ

– th

aye

oun

e. 

nstr

stu

nts 

ding

co

cros

ting

PS)

last

cm

the

ons

cret

he th

he a

nstr

thi

teri

PS)

tern

y an

urfac

form

tion

luti

laye

ers)

ure

rial

rein

e 8c

hick

inc

in 

ysty

f 15

iles

diffe

PS)

nd 

woo

urfa

5 cm

of in

ved 

tion

of

of t

ittan

 

1

i

i

+

herm

r th

nt th

ruc

udy

wh

gs i

ons

ss s

g 

)  a

ter 

m th

e i

stru

te t

hick

amo

ruct

ck)

al 

) an

nall

nd f

ce. 

m o

n of

ion

er o

), w

tha

s s

nfo

cm 

k an

line

the

yren

5cm

.  T

er 

) an

cem

od, 

ace

m th

nsu

the

n so

f th

the 

nce

 

seR

mal

hick

he 

tion

, d

hich

in G

struc

sect

m

and

inte

hick

inte

ctio

ther

kne

ount

ted 

), ad

(ro

nd  

ly 2

fina

Th

of 

f th

s in

on 

with

ane 

such

rce

thic

nd e

ed r

e u

ne (

m o

The

in 

nd 

men

ma

. T

hick

ulat

e m

olut

he 

th

e (U

 

R+

l re

kne

ene

n so

diffe

h co

Gre

ctio

tion

mate

d  e

erna

k. 

erna

on 

re i

ess 

t of

w

dhe

ock

exp

2 cm

al co

he v

air

he i

nclu

the

h va

or

h a

ed 

ck, 

exte

roo

use 

(EP

or w

e co

the

gla

nt b

arble

The

k. 

ing

main

tion

ins

ick

U va

 

alR

 

esis

ess 

ergy

olut

feren

onst

ece

on 

n o

rial

expa

ally

A 

al a

solu

is t

dif

f th

ith 

esiv

k w

pand

m t

ove

vari

r ga

insu

ude

e ou

aria

r e

as 

con

lin

erio

of c

of 

PS) 

woo

onst

e t

ass 

boa

e or

e m

g ma

n di

ns o

sula

knes

alue

 

 

stan

(m

y p

tion

nt 

titu

e we

so

of r

l 

and

y 2 

fin

and

utio

the 

ffere

he re

br

ve m

woo

ded

thic

erin

ant

ap, 

ulat

 ac

utsi

ation

extru

bitu

ncre

ned 

or to

cons

f th

or 

od f

truc

type

wo

ard 

r ce

main

ater

iffe

of a 

atin

ss o

e) w

  

nce 

m); 

erfo

n of

con

ute t

ere 

olut

rein

(po

ded 

cm

nal 

d e

ons 

sam

enc

einf

rick

mor

ol, 

d po

ck a

ng  w

ts d

an

ting

cces

ide 

n in

ude

um

ete 

wit

opc

stru

herm

gla

for t

ctio

e o

ool) 

res

eram

n l

rial

eren

bui

g m

of t

was

 

of 

�
�
 

form

f re

nstr

the 

sel

tion

nfor

oly

po

m th

cov

exte

of 

me 

ce o

forc

ks o

rtar 

gl

olys

and

with

diffe

nd 

g m

ssib

in 

n th

ed 

men 

sla

th p

coat

uctio

mal

ass 

the 

on s

of 

wi

spe

mic

laye

l an

nce 

ildi

mat

the 

 cal

 

int

– 

man

esid

ruc

bu

lect

ns 

rced

yure

lyst

hick

veri

erna

f be

co

of th

cing

of 1

for

ass 

styr

d lim

h co

er in

its 

mate

ble a

or

he 

po

sh

ab 

plas

t w

on 

l in

wo

ca

solu

ins

ith 

ctiv

c til

er 

nd U

in 

ing 

teri

in

lcul

tern

the

nce 

dent

ction

uildi

ted.

of 

d c

etha

tyre

k an

ing

al s

eam

onfig

he 

g st

18 

r th

w

rene

me 

olo

n th

po

erial

and

rder

the

lyst

heet

of 

ster

ith 

inc

nsu

ool) 

se o

utio

sula

an 

vely

es i

is 

U va

the

ele

ial. 

nsul

late

 

nal 

erm

of 

tial 

n s

ing 

  

f c

onc

ane,

ene

nd 

 w

surf

m an

gur

con

teel

cm

heir

woo

e (E

pla

r in

he u

ositi

l. T

d in

r to

erma

tyre

ts, 

15

r in

gra

clud

ulati

an

of w

ons 

ation

ou

y). 

is c

the

alue

e cr

eme

Fo

atin

ed (

sur

al 

the

bu

solu

en

colu

cret

, 

e (E

lim

with 

fac

nd w

ratio

ncre

l. A

m th

r co

ol, 

EPS

aste

n th

use

ion

The

nver

o pr

al i

ene

PV

5 c

n th

ave

des 

ion 

nd t

woo

for

n 

uter 

An

cons

e r

e 

ross

ent 

or 

ng 

(Eq

 

rfac

con

e bu

ildi

utio

nvel

umn

te 3

ex

EPS

me p

co

e o

wal

on 

ete 

As r

hick

onne

ex

S)) 

er 2

he in

e of 

 an

 fla

rted

rote

insu

e (X

VC 

cm 

e in

l or

sol

m

the 

ode

r fl

(ex

co

nd a

side

rein

s se

is l

the

lay

.1).

 (

ce (

ndu

uild

ings

ons 

lope

n 

30 

xtru

S)) 

pla

olor

of 

ll w

as 

wh

rega

k (t

ecti

xtru

coa

2.5 

nter

f an

nd 

at r

d (w

ect 

ulat

XPS

sh

thi

nter

r st

luti

mate

use

en r

oor

xtru

over

a fi

ered

nfor

ecti

oca

e fi

yer 

. 

(1)

(m
2

uctiv

ding

s in

of

e of

are

cm

ded

and

ster

r is

the

with

the

hich

ards

two

ion

ded

ated

cm

rnal

n air

the

roof

with

the

tion

S))

eet

ick

rnal

one

ons

erial

e of

roof

ring

ded

ring

final

d in

rced

ions

ated

final

the

2

.K/

vity

g 

n 

f 

f 

e 

m 

d 

d 

r 

s 

e 

h 

e 

h 

s 

o 

, 

d 

d 

m 

l 

r 

e 

f 

h 

e 

n 

. 

, 

, 

l 

e 

s 

l 

f 

f 

g 

d 

g 

l 

n 

d 

s 

d 

l 

e 

/ 

y 

co

su

of

m

Re

U

 

wh

it 

tra

or

m

th

Ta

cli

Pe

Cl

En

cli

re

lo

zo

cli

co

on

cli

zo

Fi

 

oeff

urfa

f the

axi

egu

calc
U

her

is c

ansm

rder

axi

ey 

able

ima

erfo

Ext

in

Flo

lima

nerg

ima

gio

cat

one 

ima

onsi

ne 

ima

one 

ig. 1

ficie

ace

e ai

Th

mu

ulati

 

culate

re:  �

calc

mit

Th

r to

mu

app

e 1. 

atic 

rma

Bui

elem

tern

nclin

Ext

ver

bui

elem

oori

pi

atic

gy P

Ac

atic

on. T

ed i

A)

atic

ider

the

atic

(ΤΟ

1. C

ent 

(m
2

ir g

he 

um 

ion

ed
≤

�
��

cula

ttan

he th

o fu

um 

pear

Ma

zon

ance

ildin

men

nal f

ned

tern

rtica

ildin

men

ing 

iloti

c zo

Per

ccor

c zo

The

in t

 to 

c zo

red 

ey 

c zo

ΟΤ

Clim

(W

2

.K

ap 

cal

U 

n of 

U≤

����

ated

nce 

hick

ulfil

U v

r in

Maxim

ne i

e in

ng 

nts 

flat 

roo

nal 

al 

ng 

nts 

ove

is 

one

rfor

rdin

ones

e sc

the 

the

one 

to 

are

one 

ΤΕΕ

matic

W/m

K/W

(m
2

cul

va

En

max

U

����

d (W

of t

kne

ll t

valu

n the

mum

in G

n Bu

or 

of 

er 

es o

rma

ng 

s de

chem

fou

e co

tha

be

e o

Δ 

Ε207

c zo

m.K

W); �

2

.K/

late

alue

nerg

x  

��
 –

W/m

the 

ess 

the 

ues

e G

m va

Gree

uildi

C

z

of G

ance

to 

epen

ma

ur c

olde

at is

e in

rigi

reg

701

nes

K); �

�
��

/W

d 

e p

gy P

 

– th

m
2

.K

ele

of 

con

s (ta

Gree

alue

ece 

ings

Clim

zon

0,5

0,6

0,5

Gre

e in

KE

ndi

tic 

clim

est (

s lo

n th

inal

gard

1−3

 of 

�
��

 – 

). 

U 

er 

Perf

herm

K) 

eme

the

ndi

able

ek m

e of

ac

s (Τ

mati

ne Α

50

60

50

eece

n Bu

ENA

ng 

dep

mati

(cli

cate

he n

lly 

dles

, 20

Gre

�
 – 

the

va

clim

form

 

mal 

(Eq

ent 

e ins

ition

e 1

mar

f th

cor

ΟΤ

c 

Α 

e a

uild

AK

on 

pict

c zo

ima

ed i

next

lo

ss o

010

eece

the

erm

alue

mat

man

 

tra

q. 1

(W

sula

ns 

) an

rket

herm

rding

ΕΕ2

Cl

zo

0

0

0

acco

ding

K G

the

tion

one

atic 

in a

t co

cate

of 

0). 

e (Τ

erm

al r

e w

tic 

nce 

 

ansm

); �

W/m
2

atin

of 

nd 

t. 

mal 

g to

207

ima

one 

0,45

0,50

0,45

ord

gs 

Gree

e he

n (F

es, f

zon

an a

olde

ed. 

alti

ΤΟΤΕ

mal 

resi

was 

zo

of 

mitt

�
��

2

.K

ng m

(Eq

fol

tran

o th

01−

atic 

Β 

5 

0 

5 

ding

ece 

eatin

Fig.

from

ne Δ

altit

er c

A

itud

ΤΕΕ2

res

ista

c

one 

Bu

 

tanc

��
 –

K) (t

mat

q. 2

llow

nsm

he R

−2, 2

C

g to

is

ng 

 1) 

m th

Δ).

tude

clim

All 

de a

207

sist

ance

om

as

uildi

 

ce o

– m

tabl

teri

2) a

ws i

mitta

Reg

201

Clim

zon

0,

0,

0,

o th

 di

deg

de

he w

 In

e ov

mat

reg

are 

01−

anc

e of

mpar

s de

ing

 

of t

maxi

le 1

al w

acc

inte

ance

gula

0) 

mati

ne Γ

,40 

,45 

,40 

he R

ivid

gree

efine

war

n ea

ver

tic z

gion

inc

−3, 2

ce o

f th

red 

efin

s (t

 

the 

imu

); 

was

cord

eger

e (W

ation

ic 

Γ 

Reg

ded

e da

es t

rme

ach 

r 50

zon

ns 

clud

201

of e

he a

w

ned

tabl

 

ele

um 

s ch

ding

r va

W/m

n of

Cl

z

gula

d in

ays 

the 

er (c

reg

00 m

ne t

loc

ded

10)

ext

air l

with 

d in

le 1

 (2

eme

the

hose

g to

alue

m
2

.K)

f En

lima

zone

0,3

0,4

0,3

atio

nto 

of 

reg

clim

gion

met

than

cate

d in

ern

lay

th

n th

).  

2) 

ent a

erm

en 

o th

es a

K) p

nerg

atic

e Δ

5 

40 

5 

on 

fou

eac

gion

mat

n of

ter, 

n th

ed 

n th

nal 

er 

he 

he 

as 

mal 

in 

he 

as 

er 

gy 

c 

of 

ur 

ch 

ns 

tic 

f a 

is 

he 

in 

his 

 

,  (2)

where: 

t

a

2

2

G

b

r

c

t

p

c

e

c

e

r

c

i

m

l

i

p

w

t

a

l

m

c

t

u

m

I

H

g

s

s

w

(

c

w

o

p

(

c

t

c

2

o

i

c

t

 

w

W

taki

and

2. M

2.1.

Gre

buil

resi

con

thic

poly

coa

exte

con

elem

rein

colu

is 2

mas

laye

insu

poly

with

thic

and

laye

mou

con

the 

und

mat

Incl

HD

grav

surf

slab

whi

(exp

con

with

ove

poly

(lim

cov

the 

con

2.2.

of t

in 

con

ther

U =

  

whe

W)

ing 

d the

Met

. Ty

eece

F

ldin

iden

F

nsid

ck, 

ysty

ating

ern

nsid

men

nfor

umn

25 c

son

ers 

ulat

ysty

h p

ck e

d ex

er, 

unt

nstru

ins

derl

teri

lud

DPE

vel

face

bs e

ich 

pan

ncre

h c

er p

ysty

me 

verin

in

ncre

. Th

A

the 

the

nfig

rma

  

 

R

=

ere

; �

int

e U

tho

ypic

e 

For 

ng e

ntia

For 

dere

i

yren

g w

ally

dere

nt. 

rced

n w

cm 

nry 

of 

ting

yren

plas

exte

xter

in 

ting

ucti

sula

lyin

al 

des 

E sh

-co

e 2 

etc.

di

nded

ete 

cera

pilo

yren

pla

ng 

nter

ete s

hick

As o

con

e c

gura

al tr

 

siR +

:  �
�

�
�
 –

to a

U va

ods

cal 

th

elem

al bu

th

ed a

insu

ne 

with

y 2

ed 

For

d c

with

and

is 

9 c

g m

ne 

ster 

erna

rnal

th

g po

ion

atio

ng l

(po

ma

hee

oncr

cm

 Th

iffe

d p

slab

amic

otis

ne 

aster

wit

rnal

slab

knes

obs

nstr

hoi

ation

rans

+ ∑

��
 –

– la

acco

alue

con

his 

men

uild

he 

a c

ulat

(XP

h pl

2.5 

to 

r co

conc

h th

d th

con

cm 

mat

(XP

int

ally

l su

he f

osit

n so

on l

laye

olyu

ater

et, 

rete

m th

he i

er i

poly

b o

c ti

s d

(XP

r an

th w

l su

b 15

ss o

serv

ruct

ice 

n o

smi

  

1

1

n
i

i

d

 

λ

– th

aye

oun

e. 

nstr

stu

nts 

ding

co

cros

ting

PS)

last

cm

the

ons

cret

he th

he a

nstr

thi

teri

PS)

tern

y an

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ig. 1

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mit

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r to

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atic 

rma

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ed i

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ider

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ent 

(m
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ir g

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um 

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≤

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ey 

c zo

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n of 

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ated

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r in

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ne i

e in

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rdin

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matic

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2

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max

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d (W

of t

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ll t

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n the

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n Bu

or 

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er 

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tha

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x  

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 –

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the 

ess 

the 

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m va

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C

z

of G

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to 

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ma

ur c

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at is

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– th

m
2

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ele

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ings

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0,5

0,6

0,5

Gre

e in

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ndi

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clim

est (

s lo

n th

inal

gard

1−3

 of 

�
��

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). 

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er 

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herm

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eme

the

ndi

able

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e of

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mati

ne Α

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cate

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dles

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 – 

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form

 

mal 

(Eq

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m th

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tude

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as

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tabl

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 In

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of t

maxi

le 1

al w

acc

inte

ance

gula

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mati

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,45 

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he R

ivid

gree

efine

war

n ea

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tic z

gion

inc

−3, 2

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f th

red 

efin

s (t

 

the 

imu

); 

was

cord

eger

e (W

ation

ic 

Γ 

Reg

ded

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es t

rme

ach 

r 50

zon

ns 

clud

201

of e

he a

w

ned

tabl

 

ele

um 

s ch

ding

r va

W/m

n of

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z

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d in

ays 

the 

er (c

reg

00 m

ne t

loc

ded

10)

ext

air l

with 

d in

le 1

 (2

eme

the

hose

g to

alue

m
2

.K)

f En

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0,3

0,4

0,3

atio

nto 

of 

reg

clim

gion

met

than

cate

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th

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2) 

ent a

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en 

o th

es a

K) p

nerg

atic

e Δ

5 

40 

5 

on 

fou

eac

gion

mat

n of

ter, 

n th

ed 

n th

nal 

er 

he 

he 

as 

mal 

in 

he 

as 

er 

gy 

c 

of 

ur 

ch 

ns 

tic 

f a 

is 

he 

in 

his 

 

 – maximum thermal transmittance of the element 
(W/m2.K) (table 1);

The thickness of the insulating material was chosen 
in order to fulfill the conditions of (Eq. 2) according to the 
maximum U values (table 1) and follows integer values as 
they appear in the Greek market.

Table 1. Maximum value of thermal transmittance (W/m2.K) per 
climatic zone in Greece according to the Regulation of Energy 
Performance in Buildings  (ΤΟΤΕΕ20701−2, 2010)

Building 
elements

Climatic 
zone Α

Climatic 
zone Β

Climatic 
zone Γ

Climatic 
zone Δ

External flat or 
inclined roof

0,50 0,45 0,40 0,35

External 
vertical building 

elements 
0,60 0,50 0,45 0,40

Flooring over 
pilotis

0,50 0,45 0,40 0,35

Climatic zones of Greece according to the Regulation of 
Energy Performance in Buildings

According to KENAK Greece is divided into four 
climatic zones depending on the heating degree days of 
each region. The schematic depiction (Fig. 1) defines the 
regions located in the four climatic zones, from the warmer 
(climatic zone A) to the coldest (climatic zone Δ). In each 
region of a climatic zone that is located in an altitude over 
500 meter, is considered to be in the next colder climatic 
zone than the one they are originally located. All regions 
located in climatic zone Δ regardless of altitude are included 
in this zone (ΤΟΤΕΕ20701−3, 2010).



20

Fig. 1. Climatic zones of Greece (ΤΟΤΕΕ20701−3, 2010)

2.3. Life Cycle Assessment 
The goal and scope of this LCA is to calculate the 

environmental impact of the typical constructions solutions 
of the opaque building elements and for a square meter 
cross section.

This LCA includes environmental impacts from the 
extraction and production of the material until the material 
reaches door of the factory and is ready for sale. Also includes 
the transportation from the factory to the construction site 
which is considered 100 km. The energy that is required for 
the construction of the building element in mega joules (MJ) 
is also taken into account (Αραϊλόπουλος & Χαστάς, 2009). 
The maintenance stage of the building element is included. 
The life cycle of the building element is considered 75 years. 
For the insulation 35–40 years, so it participates in the life 
cycle of the building element with two life cycles. The same 
assumption is done for the layers that need to be replaced 
along with the insulation to complete the maintenance stage. 
The color covering of the internal surface participates with 
six life cycles and the external with two in the life cycle of 
the building element. The LCA also includes environmental 
impacts from the energy that is required for the demolition 
of the construction in mega joules (MJ). Furthermore the 
transportation from the construction site after the demolition 
to the place for the final disposal of the materials which is 
considered 100 km. And at last the environmental impacts 
from the final disposal of the materials of the building 
element at the end of its life cycle. 

The materials and transportation vehicles of Life Cycle 
Inventory are secondary data from libraries (Ecoinvent 
system and unit processes, IDEMAT 2001, ETH-ESU 
system and unit processes). The energy that is required for 
the demolition and construction of the building elements 
was calculated and the production energy mix of Greece 
is also secondary data that was adapted to the latest data 
from the Energy Regulatory Authority and the Hellenic 
Transmission System Operator.

The method that was used for the life cycle assessment of 
the construction solutions is CML Baseline (Preconsultants, 
2008).  It is a classification method for LCA analysis that is 
based on the method and database of the CML University of 

Leiden (CML, 2013). For this LCA were chosen six of the 
ten impact categories of this method (table 2).

Table 2. Environmental impact categories

Environmental impact categories Units
Ozone layer depletion (ODP) kg CFC-11 equal

Photochemical oxidation (POCP) kg C2H4  equal
Global warming (GWP100) kg CO2 equal

Acidification (AP) kg SO2 equal
Abiotic depletion (ADP) kg Sb equal

Eutrophication (EP) kg PO4 equal

2.4. Multi-criteria decision analysis method TOPSIS 
The TOPSIS (Technique for Order or Preference by 

Similarity to Ideal Solution) is a method for multi-criteria 
analysis developed by Hwang and Yoon. It is based on the 
logic that the chosen alternative has the shortest distance 
from the positive ideal solution and the greater distance from 
the negative ideal solution. It is a method that compares a 
set of options by determining the weights for each criterion, 
normalizing the values   for each criterion and calculating 
the geometrical distance of each alternative and the ideal 
alternative, which is also the best value for each criterion 
(Hwang & Yoon, 1981).

In our case the alternatives are the different construction 
solutions for each building element of the building envelope. 
The criteria are the calculated environmental impact of the 
life cycle of the construction solutions in the six impact 
categories of CML Baseline method. 

For determining the weights for each criterion it was 
considered the weighting set of the method CML Baseline 
(table 3) in order to maintain the objectivity of this analysis. 

Table 3. Weighting set of method CML Baseline used in TOPSIS 
analysis

Environmental impact categories Weighting set
Ozone layer depletion (ODP) 6.74 E-11

Photochemical oxidation (POCP) 3.66 E-11
Global warming (GWP100) 8.02 E-11

Acidification (AP) 2.08 E-13
Abiotic depletion (ADP)              1.20 E-7

Eutrophication (EP) 1.21 E-10

For the identification of the positive and negative ideal 
solution because the criteria are environmental impacts 
were considered to be cost criteria.

The TOPSIS analysis was used for the ranking of 
the construction solutions of each building element of the 
building envelope, in order to provide the ideal one, and for 
each one of the four climatic zones (ΚΕΝΑΚ, 2010). 

2.5. The influence of U value in the identification of the ideal 
solution

The calculation of the thickness of the insulation 
layer was carried out for integer values as they appear in 
the Greek market. It was noticed that for a construction 
solution, in order to fulfil the conditions of the U value  
(Eq. 2), when the thickness of the insulation layer was 
high the calculated U value of the building element had 



21

significant deviation from the maximum U value. The 
construction solution with the greater thickness of insulation 
materials, as the LCA analysis and the environmental 
impacts are based on the quantities of the materials (kg) 
that compose the construction solution, appears to have the 
greater environmental impact. This was noticed mainly in 
the comparison between construction solutions that differ 
only at the kind of the insulation material. 

As a result the construction solution with the 
greater thickness and the lower U value would have more 
environmental impacts and would be far from the ideal 
solution at the final ranking of the construction solutions 
with TOPSIS. However this solution, with considerable 
distance from the maximum U value, would probably appear 
to have high improved energy performance during the life 
cycle of the building element and the building envelope. 
And probably would be one of the factors that could reduce 
the energy consumption of a building.

From this consideration it was decided after running 
the first LCA and TOPSIS analysis to carry out a second one 
where the effect of the U value in each construction solution 
and its environmental impact will be taken into account.

In order to take into account the effect of the U value it 
was necessary to provide one more weight at the weighting 
set of TOPSIS analysis for this criterion. However as in 
the first place it was decided to use the weighting set of the 
CML Baseline method, in order to preserve the objectivity 
of this analysis, the use of an extra weight would undermine 
this effort. 

So it was decided to use a typical construction that is 
provided by ISO 13790/2008 for tests, in order to quantify 
the effect of the U value in terms of energy and to be 
imported in the life cycle analysis, without providing an 
extra weight and criterion in the TOPSIS analysis.

2.6. The influence of U value in the energy performance of 
the building elements 

The software that was used for this analysis is TEE 
KENAK, the software that is used for the inspections of 
energy performance of buildings in Greece. The method 
that is used by the software is the monthly method of energy 
simulations in buildings. For the completeness of this 
analysis it was considered a theoretical heating and cooling 
system according to Regulation of Energy Performance of 
Buildings. 

The typical construction that is examined is provided 
for tests by ISO 13790/2008 (table 4) and takes no account 
of thermal bridges. 

Table 4. Dimensions of construction (ISO13790, 2008)

Building element Area (m2)
West wall 10.08

Window glazing 7.00

North wall 15.40

South wall 15.40

East wall 10.08

Floor 19.80

Roof-ceiling 19.80

In order to calculate the influence of the U value in 
the consumption of the primary energy by end use the 
maximum U value (table 1), depending on the climatic 
zone, of all building elements is defined. Then the U value 
of the examined element is changing with a descending step  
0.05 W/m2.K while all the other building elements keep their 
original maximum U value. The procedure is carried out for 
all the opaque building elements and for the four climatic 
zones of Greece. Then from the analysis and the linear 
trends of the results, the reduction in the primary energy 
consumption by end use of the building is calculated for a 
reduction of 0.01 W/m2.K of the U value of each building 
element and for the four climatic zones.

2.7. Quantification of the effect of the U value in the life 
cycle of the building element

In order to quantify the effect of the reduction of U 
value and to import it in the life cycle of each construction 
solution is taken into account the numerical distance of the 
calculated U value of the construction solution from the 
maximum U value of the climatic zone:

set of TOPSIS analysis for this criterion. However as in the 

first place it was decided to use the weighting set of the 

CML Baseline method, in order to preserve the objectivity 

of this analysis, the use of an extra weight would undermine 

this effort.  

So it was decided to use a typical construction that is 

provided by ISO 13790/2008 for tests, in order to quantify 

the effect of the U value in terms of energy and to be 

imported in the life cycle analysis, without providing an 

extra weight and criterion in the TOPSIS analysis. 

2.6. The influence of U value in the energy performance of 

the building elements  

The software that was used for this analysis is TEE 

KENAK, the software that is used for the inspections of 

energy performance of buildings in Greece. The method that 

is used by the software is the monthly method of energy 

simulations in buildings. For the completeness of this 

analysis it was considered a theoretical heating and cooling 

system according to Regulation of Energy Performance of 

Buildings.  

The typical construction that is examined is provided 

for tests by ISO 13790/2008 (table 4) and takes no account 

of thermal bridges.  

Table 4. Dimensions of construction (ISO13790, 2008) 

Building element Area (m
2

) 

West wall 10,08 

Window glazing 7,00 

North wall 15,40 

South wall 15,40 

East wall 10,08 

Floor 19,80 

Roof-ceiling 19,80 

In order to calculate the influence of the U value in the 

consumption of the primary energy by end use the 

maximum U value (table 1), depending on the climatic zone, 

of all building elements is defined. Then the U value of the 

examined element is changing with a descending step 0.05 

W/m
2

.K while all the other building elements keep their 

original maximum U
 
value. The procedure is carried out for 

all the opaque building elements and for the four climatic 

zones of Greece. Then from the analysis and the linear 

trends of the results, the reduction in the primary energy 

consumption by end use of the building is calculated for a 

reduction of 0.01 W/m
2

.K of the U value of each building 

element and for the four climatic zones. 

2.7. Quantification of the effect of the U value in the life 

cycle of the building element 

In order to quantify the effect of the reduction of U 

value and to import it in the life cycle of each construction 

solution is taken into account the numerical distance of the 

calculated U value
 
of the construction solution from the 

maximum U value of the climatic zone: 

 

 
max calculated

DU U U= −              (3) 

 

where:  �
����������

 – thermal transmittance of the element as 

it is calculated (W/m
2

.K) (Eq. 1); �
���

 – maximum thermal 

transmittance of the element (W/m
2

.K) (table 1). 

Then it is multiplied by the change in the consumption 

of primary energy by end use for a reduction of 0.01 

W/m
2

.K of the U value: 

 

  100%
U

E DU DE= × ×              (4) 

     

where:  �
�

 – the contribution of U value of the element to 

the reduction of annual primary energy consumption by end 

use (kWh/m
2

×year); �� – the numerical distance of the 

maximum and calculated U value of the building element 

(Eq. 3);  �� – the reduction in the primary energy 

consumption by end use of the building for a reduction of 

0.01 W/m
2

.K of the U value.  

This contribution is multiplied by the duration of the 

life cycle of the building elements which was considered to 

be seventy five years. 

 

'  75 
U total U

E E
−

= ×                (5) 
 

where:  �′
�������

 – the contribution of U value of the 

element to the reduction of primary energy consumption by 

end use during the life cycle of the building element 

(kWh/m
2

); �
�

 – the contribution of the U value of the 

element to the reduction of annual primary energy 

consumption by end use (kWh/m
2

×year); 75 – the duration 

of the life cycle of the building element (years).  

 Finally this contribution is converted from kWh/m2 to 
MJ/m

2

 in order to be imported in the life cycle of the 

building element. 

 

'  3.6
U total U total

E E
− −

= ×              (6) 
 
where:  �

�������
 – the contribution of U value of the 

building element to the reduction of primary energy 

consumption by end use during the life cycle of the building 

element (MJ/m
2

);  �′
�������

 – the contribution of U value of 

the building element to the reduction of primary energy 

consumption by end use during its life cycle (kWh/m
2

); 3.6 

– 1.0 kWh equals to 3.6 MJ. 

For each construction solution this contribution is 

imported as a benefit during its life cycle in the sector of 

energy.  It is added with a minus sign to the total energy that 

is required for the stages of the construction and demolition 

of the building element. 

         

 
final calculated U total

E E E
−

= −            (7) 

 

where:  �
�����

 – the final energy that is imported in the life 

cycle of the building element (MJ/m
2

);  �
����������

 – the 

total energy that is required for the construction and 

demolition of the building element (MJ/m
2

);   �
�������

– the 

contribution of U value of the building element to the 

reduction of primary energy consumption by end use during 

its life cycle of (MJ/m
2

). 

Then the LCA and TOPSIS analysis were carried out 

again with the modified data in the sector of energy. 

3. Results 

3.1. Ideal solutions from the LCA and TOSIS analysis 

,  (3)

where: 

set of TOPSIS analysis for this criterion. However as in the 

first place it was decided to use the weighting set of the 

CML Baseline method, in order to preserve the objectivity 

of this analysis, the use of an extra weight would undermine 

this effort.  

So it was decided to use a typical construction that is 

provided by ISO 13790/2008 for tests, in order to quantify 

the effect of the U value in terms of energy and to be 

imported in the life cycle analysis, without providing an 

extra weight and criterion in the TOPSIS analysis. 

2.6. The influence of U value in the energy performance of 

the building elements  

The software that was used for this analysis is TEE 

KENAK, the software that is used for the inspections of 

energy performance of buildings in Greece. The method that 

is used by the software is the monthly method of energy 

simulations in buildings. For the completeness of this 

analysis it was considered a theoretical heating and cooling 

system according to Regulation of Energy Performance of 

Buildings.  

The typical construction that is examined is provided 

for tests by ISO 13790/2008 (table 4) and takes no account 

of thermal bridges.  

Table 4. Dimensions of construction (ISO13790, 2008) 

Building element Area (m
2

) 

West wall 10,08 

Window glazing 7,00 

North wall 15,40 

South wall 15,40 

East wall 10,08 

Floor 19,80 

Roof-ceiling 19,80 

In order to calculate the influence of the U value in the 

consumption of the primary energy by end use the 

maximum U value (table 1), depending on the climatic zone, 

of all building elements is defined. Then the U value of the 

examined element is changing with a descending step 0.05 

W/m
2

.K while all the other building elements keep their 

original maximum U
 
value. The procedure is carried out for 

all the opaque building elements and for the four climatic 

zones of Greece. Then from the analysis and the linear 

trends of the results, the reduction in the primary energy 

consumption by end use of the building is calculated for a 

reduction of 0.01 W/m
2

.K of the U value of each building 

element and for the four climatic zones. 

2.7. Quantification of the effect of the U value in the life 

cycle of the building element 

In order to quantify the effect of the reduction of U 

value and to import it in the life cycle of each construction 

solution is taken into account the numerical distance of the 

calculated U value
 
of the construction solution from the 

maximum U value of the climatic zone: 

 

 
max calculated

DU U U= −              (3) 

 

where:  �
����������

 – thermal transmittance of the element as 

it is calculated (W/m
2

.K) (Eq. 1); �
���

 – maximum thermal 

transmittance of the element (W/m
2

.K) (table 1). 

Then it is multiplied by the change in the consumption 

of primary energy by end use for a reduction of 0.01 

W/m
2

.K of the U value: 

 

  100%
U

E DU DE= × ×              (4) 

     

where:  �
�

 – the contribution of U value of the element to 

the reduction of annual primary energy consumption by end 

use (kWh/m
2

×year); �� – the numerical distance of the 

maximum and calculated U value of the building element 

(Eq. 3);  �� – the reduction in the primary energy 

consumption by end use of the building for a reduction of 

0.01 W/m
2

.K of the U value.  

This contribution is multiplied by the duration of the 

life cycle of the building elements which was considered to 

be seventy five years. 

 

'  75 
U total U

E E
−

= ×                (5) 
 

where:  �′
�������

 – the contribution of U value of the 

element to the reduction of primary energy consumption by 

end use during the life cycle of the building element 

(kWh/m
2

); �
�

 – the contribution of the U value of the 

element to the reduction of annual primary energy 

consumption by end use (kWh/m
2

×year); 75 – the duration 

of the life cycle of the building element (years).  

 Finally this contribution is converted from kWh/m2 to 
MJ/m

2

 in order to be imported in the life cycle of the 

building element. 

 

'  3.6
U total U total

E E
− −

= ×              (6) 
 
where:  �

�������
 – the contribution of U value of the 

building element to the reduction of primary energy 

consumption by end use during the life cycle of the building 

element (MJ/m
2

);  �′
�������

 – the contribution of U value of 

the building element to the reduction of primary energy 

consumption by end use during its life cycle (kWh/m
2

); 3.6 

– 1.0 kWh equals to 3.6 MJ. 

For each construction solution this contribution is 

imported as a benefit during its life cycle in the sector of 

energy.  It is added with a minus sign to the total energy that 

is required for the stages of the construction and demolition 

of the building element. 

         

 
final calculated U total

E E E
−

= −            (7) 

 

where:  �
�����

 – the final energy that is imported in the life 

cycle of the building element (MJ/m
2

);  �
����������

 – the 

total energy that is required for the construction and 

demolition of the building element (MJ/m
2

);   �
�������

– the 

contribution of U value of the building element to the 

reduction of primary energy consumption by end use during 

its life cycle of (MJ/m
2

). 

Then the LCA and TOPSIS analysis were carried out 

again with the modified data in the sector of energy. 

3. Results 

3.1. Ideal solutions from the LCA and TOSIS analysis 

 – thermal transmittance of the 
element as it is calculated (W/m2.K) (Eq.  1); 

set of TOPSIS analysis for this criterion. However as in the 

first place it was decided to use the weighting set of the 

CML Baseline method, in order to preserve the objectivity 

of this analysis, the use of an extra weight would undermine 

this effort.  

So it was decided to use a typical construction that is 

provided by ISO 13790/2008 for tests, in order to quantify 

the effect of the U value in terms of energy and to be 

imported in the life cycle analysis, without providing an 

extra weight and criterion in the TOPSIS analysis. 

2.6. The influence of U value in the energy performance of 

the building elements  

The software that was used for this analysis is TEE 

KENAK, the software that is used for the inspections of 

energy performance of buildings in Greece. The method that 

is used by the software is the monthly method of energy 

simulations in buildings. For the completeness of this 

analysis it was considered a theoretical heating and cooling 

system according to Regulation of Energy Performance of 

Buildings.  

The typical construction that is examined is provided 

for tests by ISO 13790/2008 (table 4) and takes no account 

of thermal bridges.  

Table 4. Dimensions of construction (ISO13790, 2008) 

Building element Area (m
2

) 

West wall 10,08 

Window glazing 7,00 

North wall 15,40 

South wall 15,40 

East wall 10,08 

Floor 19,80 

Roof-ceiling 19,80 

In order to calculate the influence of the U value in the 

consumption of the primary energy by end use the 

maximum U value (table 1), depending on the climatic zone, 

of all building elements is defined. Then the U value of the 

examined element is changing with a descending step 0.05 

W/m
2

.K while all the other building elements keep their 

original maximum U
 
value. The procedure is carried out for 

all the opaque building elements and for the four climatic 

zones of Greece. Then from the analysis and the linear 

trends of the results, the reduction in the primary energy 

consumption by end use of the building is calculated for a 

reduction of 0.01 W/m
2

.K of the U value of each building 

element and for the four climatic zones. 

2.7. Quantification of the effect of the U value in the life 

cycle of the building element 

In order to quantify the effect of the reduction of U 

value and to import it in the life cycle of each construction 

solution is taken into account the numerical distance of the 

calculated U value
 
of the construction solution from the 

maximum U value of the climatic zone: 

 

 
max calculated

DU U U= −              (3) 

 

where:  �
����������

 – thermal transmittance of the element as 

it is calculated (W/m
2

.K) (Eq. 1); �
���

 – maximum thermal 

transmittance of the element (W/m
2

.K) (table 1). 

Then it is multiplied by the change in the consumption 

of primary energy by end use for a reduction of 0.01 

W/m
2

.K of the U value: 

 

  100%
U

E DU DE= × ×              (4) 

     

where:  �
�

 – the contribution of U value of the element to 

the reduction of annual primary energy consumption by end 

use (kWh/m
2

×year); �� – the numerical distance of the 

maximum and calculated U value of the building element 

(Eq. 3);  �� – the reduction in the primary energy 

consumption by end use of the building for a reduction of 

0.01 W/m
2

.K of the U value.  

This contribution is multiplied by the duration of the 

life cycle of the building elements which was considered to 

be seventy five years. 

 

'  75 
U total U

E E
−

= ×                (5) 
 

where:  �′
�������

 – the contribution of U value of the 

element to the reduction of primary energy consumption by 

end use during the life cycle of the building element 

(kWh/m
2

); �
�

 – the contribution of the U value of the 

element to the reduction of annual primary energy 

consumption by end use (kWh/m
2

×year); 75 – the duration 

of the life cycle of the building element (years).  

 Finally this contribution is converted from kWh/m2 to 
MJ/m

2

 in order to be imported in the life cycle of the 

building element. 

 

'  3.6
U total U total

E E
− −

= ×              (6) 
 
where:  �

�������
 – the contribution of U value of the 

building element to the reduction of primary energy 

consumption by end use during the life cycle of the building 

element (MJ/m
2

);  �′
�������

 – the contribution of U value of 

the building element to the reduction of primary energy 

consumption by end use during its life cycle (kWh/m
2

); 3.6 

– 1.0 kWh equals to 3.6 MJ. 

For each construction solution this contribution is 

imported as a benefit during its life cycle in the sector of 

energy.  It is added with a minus sign to the total energy that 

is required for the stages of the construction and demolition 

of the building element. 

         

 
final calculated U total

E E E
−

= −            (7) 

 

where:  �
�����

 – the final energy that is imported in the life 

cycle of the building element (MJ/m
2

);  �
����������

 – the 

total energy that is required for the construction and 

demolition of the building element (MJ/m
2

);   �
�������

– the 

contribution of U value of the building element to the 

reduction of primary energy consumption by end use during 

its life cycle of (MJ/m
2

). 

Then the LCA and TOPSIS analysis were carried out 

again with the modified data in the sector of energy. 

3. Results 

3.1. Ideal solutions from the LCA and TOSIS analysis 

 – maximum thermal transmittance of the element 
(W/m2.K) (table 1).

Then it is multiplied by the change in the consumption 
of primary energy by end use for a reduction of  
0.01 W/m2.K of the U value:

set of TOPSIS analysis for this criterion. However as in the 

first place it was decided to use the weighting set of the 

CML Baseline method, in order to preserve the objectivity 

of this analysis, the use of an extra weight would undermine 

this effort.  

So it was decided to use a typical construction that is 

provided by ISO 13790/2008 for tests, in order to quantify 

the effect of the U value in terms of energy and to be 

imported in the life cycle analysis, without providing an 

extra weight and criterion in the TOPSIS analysis. 

2.6. The influence of U value in the energy performance of 

the building elements  

The software that was used for this analysis is TEE 

KENAK, the software that is used for the inspections of 

energy performance of buildings in Greece. The method that 

is used by the software is the monthly method of energy 

simulations in buildings. For the completeness of this 

analysis it was considered a theoretical heating and cooling 

system according to Regulation of Energy Performance of 

Buildings.  

The typical construction that is examined is provided 

for tests by ISO 13790/2008 (table 4) and takes no account 

of thermal bridges.  

Table 4. Dimensions of construction (ISO13790, 2008) 

Building element Area (m
2

) 

West wall 10,08 

Window glazing 7,00 

North wall 15,40 

South wall 15,40 

East wall 10,08 

Floor 19,80 

Roof-ceiling 19,80 

In order to calculate the influence of the U value in the 

consumption of the primary energy by end use the 

maximum U value (table 1), depending on the climatic zone, 

of all building elements is defined. Then the U value of the 

examined element is changing with a descending step 0.05 

W/m
2

.K while all the other building elements keep their 

original maximum U
 
value. The procedure is carried out for 

all the opaque building elements and for the four climatic 

zones of Greece. Then from the analysis and the linear 

trends of the results, the reduction in the primary energy 

consumption by end use of the building is calculated for a 

reduction of 0.01 W/m
2

.K of the U value of each building 

element and for the four climatic zones. 

2.7. Quantification of the effect of the U value in the life 

cycle of the building element 

In order to quantify the effect of the reduction of U 

value and to import it in the life cycle of each construction 

solution is taken into account the numerical distance of the 

calculated U value
 
of the construction solution from the 

maximum U value of the climatic zone: 

 

 
max calculated

DU U U= −              (3) 

 

where:  �
����������

 – thermal transmittance of the element as 

it is calculated (W/m
2

.K) (Eq. 1); �
���

 – maximum thermal 

transmittance of the element (W/m
2

.K) (table 1). 

Then it is multiplied by the change in the consumption 

of primary energy by end use for a reduction of 0.01 

W/m
2

.K of the U value: 

 

  100 %
U

E DU DE= × ×              (4) 

     

where:  �
�

 – the contribution of U value of the element to 

the reduction of annual primary energy consumption by end 

use (kWh/m
2

×year); �� – the numerical distance of the 

maximum and calculated U value of the building element 

(Eq. 3);  �� – the reduction in the primary energy 

consumption by end use of the building for a reduction of 

0.01 W/m
2

.K of the U value.  

This contribution is multiplied by the duration of the 

life cycle of the building elements which was considered to 

be seventy five years. 

 

'  75 
U total U

E E
−

= ×                (5) 
 

where:  �′
�������

 – the contribution of U value of the 

element to the reduction of primary energy consumption by 

end use during the life cycle of the building element 

(kWh/m
2

); �
�

 – the contribution of the U value of the 

element to the reduction of annual primary energy 

consumption by end use (kWh/m
2

×year); 75 – the duration 

of the life cycle of the building element (years).  

 Finally this contribution is converted from kWh/m2 to 
MJ/m

2

 in order to be imported in the life cycle of the 

building element. 

 

'  3.6
U total U total

E E
− −

= ×              (6) 
 
where:  �

�������
 – the contribution of U value of the 

building element to the reduction of primary energy 

consumption by end use during the life cycle of the building 

element (MJ/m
2

);  �′
�������

 – the contribution of U value of 

the building element to the reduction of primary energy 

consumption by end use during its life cycle (kWh/m
2

); 3.6 

– 1.0 kWh equals to 3.6 MJ. 

For each construction solution this contribution is 

imported as a benefit during its life cycle in the sector of 

energy.  It is added with a minus sign to the total energy that 

is required for the stages of the construction and demolition 

of the building element. 

         

 
final calculated U total

E E E
−

= −            (7) 

 

where:  �
�����

 – the final energy that is imported in the life 

cycle of the building element (MJ/m
2

);  �
����������

 – the 

total energy that is required for the construction and 

demolition of the building element (MJ/m
2

);   �
�������

– the 

contribution of U value of the building element to the 

reduction of primary energy consumption by end use during 

its life cycle of (MJ/m
2

). 

Then the LCA and TOPSIS analysis were carried out 

again with the modified data in the sector of energy. 

3. Results 

3.1. Ideal solutions from the LCA and TOSIS analysis 

,  (4)

where: EU – the contribution of U value of the 
element to the reduction of annual primary 
energy consumption by end use (kWh/m2 ×year); 
DU – the numerical distance of the maximum and 
calculated U value of the building element (Eq. 3); DE – 
the reduction in the primary energy consumption by end 
use of the building for a reduction of 0.01 W/m2.K of the 
U value. 

This contribution is multiplied by the duration of the 
life cycle of the building elements which was considered to 
be seventy five years.

set of TOPSIS analysis for this criterion. However as in the 

first place it was decided to use the weighting set of the 

CML Baseline method, in order to preserve the objectivity 

of this analysis, the use of an extra weight would undermine 

this effort.  

So it was decided to use a typical construction that is 

provided by ISO 13790/2008 for tests, in order to quantify 

the effect of the U value in terms of energy and to be 

imported in the life cycle analysis, without providing an 

extra weight and criterion in the TOPSIS analysis. 

2.6. The influence of U value in the energy performance of 

the building elements  

The software that was used for this analysis is TEE 

KENAK, the software that is used for the inspections of 

energy performance of buildings in Greece. The method that 

is used by the software is the monthly method of energy 

simulations in buildings. For the completeness of this 

analysis it was considered a theoretical heating and cooling 

system according to Regulation of Energy Performance of 

Buildings.  

The typical construction that is examined is provided 

for tests by ISO 13790/2008 (table 4) and takes no account 

of thermal bridges.  

Table 4. Dimensions of construction (ISO13790, 2008) 

Building element Area (m
2

) 

West wall 10,08 

Window glazing 7,00 

North wall 15,40 

South wall 15,40 

East wall 10,08 

Floor 19,80 

Roof-ceiling 19,80 

In order to calculate the influence of the U value in the 

consumption of the primary energy by end use the 

maximum U value (table 1), depending on the climatic zone, 

of all building elements is defined. Then the U value of the 

examined element is changing with a descending step 0.05 

W/m
2

.K while all the other building elements keep their 

original maximum U
 
value. The procedure is carried out for 

all the opaque building elements and for the four climatic 

zones of Greece. Then from the analysis and the linear 

trends of the results, the reduction in the primary energy 

consumption by end use of the building is calculated for a 

reduction of 0.01 W/m
2

.K of the U value of each building 

element and for the four climatic zones. 

2.7. Quantification of the effect of the U value in the life 

cycle of the building element 

In order to quantify the effect of the reduction of U 

value and to import it in the life cycle of each construction 

solution is taken into account the numerical distance of the 

calculated U value
 
of the construction solution from the 

maximum U value of the climatic zone: 

 

 
max calculated

DU U U= −              (3) 

 

where:  �
����������

 – thermal transmittance of the element as 

it is calculated (W/m
2

.K) (Eq. 1); �
���

 – maximum thermal 

transmittance of the element (W/m
2

.K) (table 1). 

Then it is multiplied by the change in the consumption 

of primary energy by end use for a reduction of 0.01 

W/m
2

.K of the U value : 

 

  100%
U

E DU DE= × ×              (4) 

     

where:  �
�

 – the contribution of U value of the element to 

the reduction of annual primary energy consumption by end 

use (kWh/m
2

×year); �� – the numerical distance of the 

maximum and calculated U value of the building element 

(Eq. 3);  �� – the reduction in the primary energy 

consumption by end use of the building for a reduction of 

0.01 W/m
2

.K of the U value.  

This contribution is multiplied by the duration of the 

life cycle of the building elements which was considered to 

be seventy five years. 

 

'  75 
U total U

E E
−

= ×                (5) 
 

where:  �′
�������

 – the contribution of U value of the 

element to the reduction of primary energy consumption by 

end use during the life cycle of the building element 

(kWh/m
2

); �
�

 – the contribution of the U value of the 

element to the reduction of annual primary energy 

consumption by end use (kWh/m
2

×year); 75 – the duration 

of the life cycle of the building element (years).  

 Finally this contribution is converted from kWh/m2 to 
MJ/m

2

 in order to be imported in the life cycle of the 

building element. 

 

'  3.6
U total U total

E E
− −

= ×              (6) 
 
where:  �

�������
 – the contribution of U value of the 

building element to the reduction of primary energy 

consumption by end use during the life cycle of the building 

element (MJ/m
2

);  �′
�������

 – the contribution of U value of 

the building element to the reduction of primary energy 

consumption by end use during its life cycle (kWh/m
2

); 3.6 

– 1.0 kWh equals to 3.6 MJ. 

For each construction solution this contribution is 

imported as a benefit during its life cycle in the sector of 

energy.  It is added with a minus sign to the total energy that 

is required for the stages of the construction and demolition 

of the building element. 

         

 
final calculated U total

E E E
−

= −            (7) 

 

where:  �
�����

 – the final energy that is imported in the life 

cycle of the building element (MJ/m
2

);  �
����������

 – the 

total energy that is required for the construction and 

demolition of the building element (MJ/m
2

);   �
�������

– the 

contribution of U value of the building element to the 

reduction of primary energy consumption by end use during 

its life cycle of (MJ/m
2

). 

Then the LCA and TOPSIS analysis were carried out 

again with the modified data in the sector of energy. 

3. Results 

3.1. Ideal solutions from the LCA and TOSIS analysis 

, (5)

where: 

set of TOPSIS analysis for this criterion. However as in the 

first place it was decided to use the weighting set of the 

CML Baseline method, in order to preserve the objectivity 

of this analysis, the use of an extra weight would undermine 

this effort.  

So it was decided to use a typical construction that is 

provided by ISO 13790/2008 for tests, in order to quantify 

the effect of the U value in terms of energy and to be 

imported in the life cycle analysis, without providing an 

extra weight and criterion in the TOPSIS analysis. 

2.6. The influence of U value in the energy performance of 

the building elements  

The software that was used for this analysis is TEE 

KENAK, the software that is used for the inspections of 

energy performance of buildings in Greece. The method that 

is used by the software is the monthly method of energy 

simulations in buildings. For the completeness of this 

analysis it was considered a theoretical heating and cooling 

system according to Regulation of Energy Performance of 

Buildings.  

The typical construction that is examined is provided 

for tests by ISO 13790/2008 (table 4) and takes no account 

of thermal bridges.  

Table 4. Dimensions of construction (ISO13790, 2008) 

Building element Area (m
2

) 

West wall 10,08 

Window glazing 7,00 

North wall 15,40 

South wall 15,40 

East wall 10,08 

Floor 19,80 

Roof-ceiling 19,80 

In order to calculate the influence of the U value in the 

consumption of the primary energy by end use the 

maximum U value (table 1), depending on the climatic zone, 

of all building elements is defined. Then the U value of the 

examined element is changing with a descending step 0.05 

W/m
2

.K while all the other building elements keep their 

original maximum U
 
value. The procedure is carried out for 

all the opaque building elements and for the four climatic 

zones of Greece. Then from the analysis and the linear 

trends of the results, the reduction in the primary energy 

consumption by end use of the building is calculated for a 

reduction of 0.01 W/m
2

.K of the U value of each building 

element and for the four climatic zones. 

2.7. Quantification of the effect of the U value in the life 

cycle of the building element 

In order to quantify the effect of the reduction of U 

value and to import it in the life cycle of each construction 

solution is taken into account the numerical distance of the 

calculated U value
 
of the construction solution from the 

maximum U value of the climatic zone: 

 

 
max calculated

DU U U= −              (3) 

 

where:  �
����������

 – thermal transmittance of the element as 

it is calculated (W/m
2

.K) (Eq. 1); �
���

 – maximum thermal 

transmittance of the element (W/m
2

.K) (table 1). 

Then it is multiplied by the change in the consumption 

of primary energy by end use for a reduction of 0.01 

W/m
2

.K of the U value: 

 

  100%
U

E DU DE= × ×              (4) 

     

where:  �
�

 – the contribution of U value of the element to 

the reduction of annual primary energy consumption by end 

use (kWh/m
2

×year); �� – the numerical distance of the 

maximum and calculated U value of the building element 

(Eq. 3);  �� – the reduction in the primary energy 

consumption by end use of the building for a reduction of 

0.01 W/m
2

.K of the U value.  

This contribution is multiplied by the duration of the 

life cycle of the building elements which was considered to 

be seventy five years. 

 

'   
U total

E
−

               (5) 
 

where:  �′
�������

 – the contribution of U value of the 

element to the reduction of primary energy consumption by 

end use during the life cycle of the building element 

(kWh/m
2

); �
�

 – the contribution of the U value of the 

element to the reduction of annual primary energy 

consumption by end use (kWh/m
2

×year); 75 – the duration 

of the life cycle of the building element (years).  

 Finally this contribution is converted from kWh/m2 to 
MJ/m

2

 in order to be imported in the life cycle of the 

building element. 

 

'  3.6
U total U total

E E
− −

= ×              (6) 
 
where:  �

�������
 – the contribution of U value of the 

building element to the reduction of primary energy 

consumption by end use during the life cycle of the building 

element (MJ/m
2

);  �′
�������

 – the contribution of U value of 

the building element to the reduction of primary energy 

consumption by end use during its life cycle (kWh/m
2

); 3.6 

– 1.0 kWh equals to 3.6 MJ. 

For each construction solution this contribution is 

imported as a benefit during its life cycle in the sector of 

energy.  It is added with a minus sign to the total energy that 

is required for the stages of the construction and demolition 

of the building element. 

         

 
final calculated U total

E E E
−

= −            (7) 

 

where:  �
�����

 – the final energy that is imported in the life 

cycle of the building element (MJ/m
2

);  �
����������

 – the 

total energy that is required for the construction and 

demolition of the building element (MJ/m
2

);   �
�������

– the 

contribution of U value of the building element to the 

reduction of primary energy consumption by end use during 

its life cycle of (MJ/m
2

). 

Then the LCA and TOPSIS analysis were carried out 

again with the modified data in the sector of energy. 

3. Results 

3.1. Ideal solutions from the LCA and TOSIS analysis 

 – the contribution of U value of the element 
to the reduction of primary energy consumption by end use 
during the life cycle of the building element (kWh/m2); 
EU – the contribution of the U value of the element to the 
reduction of annual primary energy consumption by end use 
(kWh/m2×year); 75 – the duration of the life cycle of the 
building element (years). 

Finally this contribution is converted from kWh/m2 
to MJ/m2 in order to be imported in the life cycle of the 
building element.

set of TOPSIS analysis for this criterion. However as in the 

first place it was decided to use the weighting set of the 

CML Baseline method, in order to preserve the objectivity 

of this analysis, the use of an extra weight would undermine 

this effort.  

So it was decided to use a typical construction that is 

provided by ISO 13790/2008 for tests, in order to quantify 

the effect of the U value in terms of energy and to be 

imported in the life cycle analysis, without providing an 

extra weight and criterion in the TOPSIS analysis. 

2.6. The influence of U value in the energy performance of 

the building elements  

The software that was used for this analysis is TEE 

KENAK, the software that is used for the inspections of 

energy performance of buildings in Greece. The method that 

is used by the software is the monthly method of energy 

simulations in buildings. For the completeness of this 

analysis it was considered a theoretical heating and cooling 

system according to Regulation of Energy Performance of 

Buildings.  

The typical construction that is examined is provided 

for tests by ISO 13790/2008 (table 4) and takes no account 

of thermal bridges.  

Table 4. Dimensions of construction (ISO13790, 2008) 

Building element Area (m
2

) 

West wall 10,08 

Window glazing 7,00 

North wall 15,40 

South wall 15,40 

East wall 10,08 

Floor 19,80 

Roof-ceiling 19,80 

In order to calculate the influence of the U value in the 

consumption of the primary energy by end use the 

maximum U value (table 1), depending on the climatic zone, 

of all building elements is defined. Then the U value of the 

examined element is changing with a descending step 0.05 

W/m
2

.K while all the other building elements keep their 

original maximum U
 
value. The procedure is carried out for 

all the opaque building elements and for the four climatic 

zones of Greece. Then from the analysis and the linear 

trends of the results, the reduction in the primary energy 

consumption by end use of the building is calculated for a 

reduction of 0.01 W/m
2

.K of the U value of each building 

element and for the four climatic zones. 

2.7. Quantification of the effect of the U value in the life 

cycle of the building element 

In order to quantify the effect of the reduction of U 

value and to import it in the life cycle of each construction 

solution is taken into account the numerical distance of the 

calculated U value
 
of the construction solution from the 

maximum U value of the climatic zone: 

 

 
max calculated

DU U U= −              (3) 

 

where:  �
����������

 – thermal transmittance of the element as 

it is calculated (W/m
2

.K) (Eq. 1); �
���

 – maximum thermal 

transmittance of the element (W/m
2

.K) (table 1). 

Then it is multiplied by the change in the consumption 

of primary energy by end use for a reduction of 0.01 

W/m
2

.K of the U value: 

 

  100%
U

E DU DE= × ×              (4) 

     

where:  �
�

 – the contribution of U value of the element to 

the reduction of annual primary energy consumption by end 

use (kWh/m
2

×year); �� – the numerical distance of the 

maximum and calculated U value of the building element 

(Eq. 3);  �� – the reduction in the primary energy 

consumption by end use of the building for a reduction of 

0.01 W/m
2

.K of the U value.  

This contribution is multiplied by the duration of the 

life cycle of the building elements which was considered to 

be seventy five years. 

 

'  75 
U total U

E E
−

= ×                (5) 
 

where:  �′
�������

 – the contribution of U value of the 

element to the reduction of primary energy consumption by 

end use during the life cycle of the building element 

(kWh/m
2

); �
�

 – the contribution of the U value of the 

element to the reduction of annual primary energy 

consumption by end use (kWh/m
2

×year); 75 – the duration 

of the life cycle of the building element (years).  

 Finally this contribution is converted from kWh/m2 to 
MJ/m

2

 in order to be imported in the life cycle of the 

building element. 

 

'  3.6
U total U total

E E
− −

= ×              (6) 
 
where:  �

�������
 – the contribution of U value of the 

building element to the reduction of primary energy 

consumption by end use during the life cycle of the building 

element (MJ/m
2

);  �′
�������

 – the contribution of U value of 

the building element to the reduction of primary energy 

consumption by end use during its life cycle (kWh/m
2

); 3.6 

– 1.0 kWh equals to 3.6 MJ. 

For each construction solution this contribution is 

imported as a benefit during its life cycle in the sector of 

energy.  It is added with a minus sign to the total energy that 

is required for the stages of the construction and demolition 

of the building element. 

         

 
final calculated U total

E E E
−

= −            (7) 

 

where:  �
�����

 – the final energy that is imported in the life 

cycle of the building element (MJ/m
2

);  �
����������

 – the 

total energy that is required for the construction and 

demolition of the building element (MJ/m
2

);   �
�������

– the 

contribution of U value of the building element to the 

reduction of primary energy consumption by end use during 

its life cycle of (MJ/m
2

). 

Then the LCA and TOPSIS analysis were carried out 

again with the modified data in the sector of energy. 

3. Results 

3.1. Ideal solutions from the LCA and TOSIS analysis 

,  (6)



22

where: 

set of TOPSIS analysis for this criterion. However as in the 

first place it was decided to use the weighting set of the 

CML Baseline method, in order to preserve the objectivity 

of this analysis, the use of an extra weight would undermine 

this effort.  

So it was decided to use a typical construction that is 

provided by ISO 13790/2008 for tests, in order to quantify 

the effect of the U value in terms of energy and to be 

imported in the life cycle analysis, without providing an 

extra weight and criterion in the TOPSIS analysis. 

2.6. The influence of U value in the energy performance of 

the building elements  

The software that was used for this analysis is TEE 

KENAK, the software that is used for the inspections of 

energy performance of buildings in Greece. The method that 

is used by the software is the monthly method of energy 

simulations in buildings. For the completeness of this 

analysis it was considered a theoretical heating and cooling 

system according to Regulation of Energy Performance of 

Buildings.  

The typical construction that is examined is provided 

for tests by ISO 13790/2008 (table 4) and takes no account 

of thermal bridges.  

Table 4. Dimensions of construction (ISO13790, 2008) 

Building element Area (m
2

) 

West wall 10,08 

Window glazing 7,00 

North wall 15,40 

South wall 15,40 

East wall 10,08 

Floor 19,80 

Roof-ceiling 19,80 

In order to calculate the influence of the U value in the 

consumption of the primary energy by end use the 

maximum U value (table 1), depending on the climatic zone, 

of all building elements is defined. Then the U value of the 

examined element is changing with a descending step 0.05 

W/m
2

.K while all the other building elements keep their 

original maximum U
 
value. The procedure is carried out for 

all the opaque building elements and for the four climatic 

zones of Greece. Then from the analysis and the linear 

trends of the results, the reduction in the primary energy 

consumption by end use of the building is calculated for a 

reduction of 0.01 W/m
2

.K of the U value of each building 

element and for the four climatic zones. 

2.7. Quantification of the effect of the U value in the life 

cycle of the building element 

In order to quantify the effect of the reduction of U 

value and to import it in the life cycle of each construction 

solution is taken into account the numerical distance of the 

calculated U value
 
of the construction solution from the 

maximum U value of the climatic zone: 

 

 
max calculated

DU U U= −              (3) 

 

where:  �
����������

 – thermal transmittance of the element as 

it is calculated (W/m
2

.K) (Eq. 1); �
���

 – maximum thermal 

transmittance of the element (W/m
2

.K) (table 1). 

Then it is multiplied by the change in the consumption 

of primary energy by end use for a reduction of 0.01 

W/m
2

.K of the U value: 

 

  100%
U

E DU DE= × ×              (4) 

     

where:  �
�

 – the contribution of U value of the element to 

the reduction of annual primary energy consumption by end 

use (kWh/m
2

×year); �� – the numerical distance of the 

maximum and calculated U value of the building element 

(Eq. 3);  �� – the reduction in the primary energy 

consumption by end use of the building for a reduction of 

0.01 W/m
2

.K of the U value.  

This contribution is multiplied by the duration of the 

life cycle of the building elements which was considered to 

be seventy five years. 

 

'  75 
U total U

E E
−

= ×                (5) 
 

where:  �′
�������

 – the contribution of U value of the 

element to the reduction of primary energy consumption by 

end use during the life cycle of the building element 

(kWh/m
2

); �
�

 – the contribution of the U value of the 

element to the reduction of annual primary energy 

consumption by end use (kWh/m
2

×year); 75 – the duration 

of the life cycle of the building element (years).  

 Finally this contribution is converted from kWh/m2 to 
MJ/m

2

 in order to be imported in the life cycle of the 

building element. 

 

'  3.6
U total U total

E E
− −

             (6) 
 
where:  �

�������
 – the contribution of U value of the 

building element to the reduction of primary energy 

consumption by end use during the life cycle of the building 

element (MJ/m
2

);  �′
�������

 – the contribution of U value of 

the building element to the reduction of primary energy 

consumption by end use during its life cycle (kWh/m
2

); 3.6 

– 1.0 kWh equals to 3.6 MJ. 

For each construction solution this contribution is 

imported as a benefit during its life cycle in the sector of 

energy.  It is added with a minus sign to the total energy that 

is required for the stages of the construction and demolition 

of the building element. 

         

 
final calculated U total

E E E
−

= −            (7) 

 

where:  �
�����

 – the final energy that is imported in the life 

cycle of the building element (MJ/m
2

);  �
����������

 – the 

total energy that is required for the construction and 

demolition of the building element (MJ/m
2

);   �
�������

– the 

contribution of U value of the building element to the 

reduction of primary energy consumption by end use during 

its life cycle of (MJ/m
2

). 

Then the LCA and TOPSIS analysis were carried out 

again with the modified data in the sector of energy. 

3. Results 

3.1. Ideal solutions from the LCA and TOSIS analysis 

 – the contribution of U value of the building 
element to the reduction of primary energy consumption 
by end use during the life cycle of the building element  
(MJ/m2); 

set of TOPSIS analysis for this criterion. However as in the 

first place it was decided to use the weighting set of the 

CML Baseline method, in order to preserve the objectivity 

of this analysis, the use of an extra weight would undermine 

this effort.  

So it was decided to use a typical construction that is 

provided by ISO 13790/2008 for tests, in order to quantify 

the effect of the U value in terms of energy and to be 

imported in the life cycle analysis, without providing an 

extra weight and criterion in the TOPSIS analysis. 

2.6. The influence of U value in the energy performance of 

the building elements  

The software that was used for this analysis is TEE 

KENAK, the software that is used for the inspections of 

energy performance of buildings in Greece. The method that 

is used by the software is the monthly method of energy 

simulations in buildings. For the completeness of this 

analysis it was considered a theoretical heating and cooling 

system according to Regulation of Energy Performance of 

Buildings.  

The typical construction that is examined is provided 

for tests by ISO 13790/2008 (table 4) and takes no account 

of thermal bridges.  

Table 4. Dimensions of construction (ISO13790, 2008) 

Building element Area (m
2

) 

West wall 10,08 

Window glazing 7,00 

North wall 15,40 

South wall 15,40 

East wall 10,08 

Floor 19,80 

Roof-ceiling 19,80 

In order to calculate the influence of the U value in the 

consumption of the primary energy by end use the 

maximum U value (table 1), depending on the climatic zone, 

of all building elements is defined. Then the U value of the 

examined element is changing with a descending step 0.05 

W/m
2

.K while all the other building elements keep their 

original maximum U
 
value. The procedure is carried out for 

all the opaque building elements and for the four climatic 

zones of Greece. Then from the analysis and the linear 

trends of the results, the reduction in the primary energy 

consumption by end use of the building is calculated for a 

reduction of 0.01 W/m
2

.K of the U value of each building 

element and for the four climatic zones. 

2.7. Quantification of the effect of the U value in the life 

cycle of the building element 

In order to quantify the effect of the reduction of U 

value and to import it in the life cycle of each construction 

solution is taken into account the numerical distance of the 

calculated U value
 
of the construction solution from the 

maximum U value of the climatic zone: 

 

 
max calculated

DU U U= −              (3) 

 

where:  �
����������

 – thermal transmittance of the element as 

it is calculated (W/m
2

.K) (Eq. 1); �
���

 – maximum thermal 

transmittance of the element (W/m
2

.K) (table 1). 

Then it is multiplied by the change in the consumption 

of primary energy by end use for a reduction of 0.01 

W/m
2

.K of the U value: 

 

  100%
U

E DU DE= × ×              (4) 

     

where:  �
�

 – the contribution of U value of the element to 

the reduction of annual primary energy consumption by end 

use (kWh/m
2

×year); �� – the numerical distance of the 

maximum and calculated U value of the building element 

(Eq. 3);  �� – the reduction in the primary energy 

consumption by end use of the building for a reduction of 

0.01 W/m
2

.K of the U value.  

This contribution is multiplied by the duration of the 

life cycle of the building elements which was considered to 

be seventy five years. 

 

'  75 
U total U

E E
−

= ×                (5) 
 

where:  �′
�������

 – the contribution of U value of the 

element to the reduction of primary energy consumption by 

end use during the life cycle of the building element 

(kWh/m
2

); �
�

 – the contribution of the U value of the 

element to the reduction of annual primary energy 

consumption by end use (kWh/m
2

×year); 75 – the duration 

of the life cycle of the building element (years).  

 Finally this contribution is converted from kWh/m2 to 
MJ/m

2

 in order to be imported in the life cycle of the 

building element. 

 

'  
U total U total

E E
− −

             (6) 
 
where:  �

�������
 – the contribution of U value of the 

building element to the reduction of primary energy 

consumption by end use during the life cycle of the building 

element (MJ/m
2

);  �′
�������

 – the contribution of U value of 

the building element to the reduction of primary energy 

consumption by end use during its life cycle (kWh/m
2

); 3.6 

– 1.0 kWh equals to 3.6 MJ. 

For each construction solution this contribution is 

imported as a benefit during its life cycle in the sector of 

energy.  It is added with a minus sign to the total energy that 

is required for the stages of the construction and demolition 

of the building element. 

         

 
final calculated U total

E E E
−

= −            (7) 

 

where:  �
�����

 – the final energy that is imported in the life 

cycle of the building element (MJ/m
2

);  �
����������

 – the 

total energy that is required for the construction and 

demolition of the building element (MJ/m
2

);   �
�������

– the 

contribution of U value of the building element to the 

reduction of primary energy consumption by end use during 

its life cycle of (MJ/m
2

). 

Then the LCA and TOPSIS analysis were carried out 

again with the modified data in the sector of energy. 

3. Results 

3.1. Ideal solutions from the LCA and TOSIS analysis 

 – the contribution of U value of the 
building element to the reduction of primary energy 
consumption by end use during its life cycle (kWh/m2); 
3.6–1.0 kWh equals to 3.6 MJ.

For each construction solution this contribution is 
imported as a benefit during its life cycle in the sector of 
energy. It is added with a minus sign to the total energy that 
is required for the stages of the construction and demolition 
of the building element.

set of TOPSIS analysis for this criterion. However as in the 

first place it was decided to use the weighting set of the 

CML Baseline method, in order to preserve the objectivity 

of this analysis, the use of an extra weight would undermine 

this effort.  

So it was decided to use a typical construction that is 

provided by ISO 13790/2008 for tests, in order to quantify 

the effect of the U value in terms of energy and to be 

imported in the life cycle analysis, without providing an 

extra weight and criterion in the TOPSIS analysis. 

2.6. The influence of U value in the energy performance of 

the building elements  

The software that was used for this analysis is TEE 

KENAK, the software that is used for the inspections of 

energy performance of buildings in Greece. The method that 

is used by the software is the monthly method of energy 

simulations in buildings. For the completeness of this 

analysis it was considered a theoretical heating and cooling 

system according to Regulation of Energy Performance of 

Buildings.  

The typical construction that is examined is provided 

for tests by ISO 13790/2008 (table 4) and takes no account 

of thermal bridges.  

Table 4. Dimensions of construction (ISO13790, 2008) 

Building element Area (m
2

) 

West wall 10,08 

Window glazing 7,00 

North wall 15,40 

South wall 15,40 

East wall 10,08 

Floor 19,80 

Roof-ceiling 19,80 

In order to calculate the influence of the U value in the 

consumption of the primary energy by end use the 

maximum U value (table 1), depending on the climatic zone, 

of all building elements is defined. Then the U value of the 

examined element is changing with a descending step 0.05 

W/m
2

.K while all the other building elements keep their 

original maximum U
 
value. The procedure is carried out for 

all the opaque building elements and for the four climatic 

zones of Greece. Then from the analysis and the linear 

trends of the results, the reduction in the primary energy 

consumption by end use of the building is calculated for a 

reduction of 0.01 W/m
2

.K of the U value of each building 

element and for the four climatic zones. 

2.7. Quantification of the effect of the U value in the life 

cycle of the building element 

In order to quantify the effect of the reduction of U 

value and to import it in the life cycle of each construction 

solution is taken into account the numerical distance of the 

calculated U value
 
of the construction solution from the 

maximum U value of the climatic zone: 

 

 
max calculated

DU U U= −              (3) 

 

where:  �
����������

 – thermal transmittance of the element as 

it is calculated (W/m
2

.K) (Eq. 1); �
���

 – maximum thermal 

transmittance of the element (W/m
2

.K) (table 1). 

Then it is multiplied by the change in the consumption 

of primary energy by end use for a reduction of 0.01 

W/m
2

.K of the U value: 

 

  100%
U

E DU DE= × ×              (4) 

     

where:  �
�

 – the contribution of U value of the element to 

the reduction of annual primary energy consumption by end 

use (kWh/m
2

×year); �� – the numerical distance of the 

maximum and calculated U value of the building element 

(Eq. 3);  �� – the reduction in the primary energy 

consumption by end use of the building for a reduction of 

0.01 W/m
2

.K of the U value.  

This contribution is multiplied by the duration of the 

life cycle of the building elements which was considered to 

be seventy five years. 

 

'  75 
U total U

E E
−

= ×                (5) 
 

where:  �′
�������

 – the contribution of U value of the 

element to the reduction of primary energy consumption by 

end use during the life cycle of the building element 

(kWh/m
2

); �
�

 – the contribution of the U value of the 

element to the reduction of annual primary energy 

consumption by end use (kWh/m
2

×year); 75 – the duration 

of the life cycle of the building element (years).  

 Finally this contribution is converted from kWh/m2 to 
MJ/m

2

 in order to be imported in the life cycle of the 

building element. 

 

'  3.6
U total U total

E E
− −

= ×              (6) 
 
where:  �

�������
 – the contribution of U value of the 

building element to the reduction of primary energy 

consumption by end use during the life cycle of the building 

element (MJ/m
2

);  �′
�������

 – the contribution of U value of 

the building element to the reduction of primary energy 

consumption by end use during its life cycle (kWh/m
2

); 3.6 

– 1.0 kWh equals to 3.6 MJ. 

For each construction solution this contribution is 

imported as a benefit during its life cycle in the sector of 

energy.  It is added with a minus sign to the total energy that 

is required for the stages of the construction and demolition 

of the building element. 

         

 
final calculated U total

E E E
−

= −            (7) 

 

where:  �
�����

 – the final energy that is imported in the life 

cycle of the building element (MJ/m
2

);  �
����������

 – the 

total energy that is required for the construction and 

demolition of the building element (MJ/m
2

);   �
�������

– the 

contribution of U value of the building element to the 

reduction of primary energy consumption by end use during 

its life cycle of (MJ/m
2

). 

Then the LCA and TOPSIS analysis were carried out 

again with the modified data in the sector of energy. 

3. Results 

3.1. Ideal solutions from the LCA and TOSIS analysis 

,  (7)

where: 

set of TOPSIS analysis for this criterion. However as in the 

first place it was decided to use the weighting set of the 

CML Baseline method, in order to preserve the objectivity 

of this analysis, the use of an extra weight would undermine 

this effort.  

So it was decided to use a typical construction that is 

provided by ISO 13790/2008 for tests, in order to quantify 

the effect of the U value in terms of energy and to be 

imported in the life cycle analysis, without providing an 

extra weight and criterion in the TOPSIS analysis. 

2.6. The influence of U value in the energy performance of 

the building elements  

The software that was used for this analysis is TEE 

KENAK, the software that is used for the inspections of 

energy performance of buildings in Greece. The method that 

is used by the software is the monthly method of energy 

simulations in buildings. For the completeness of this 

analysis it was considered a theoretical heating and cooling 

system according to Regulation of Energy Performance of 

Buildings.  

The typical construction that is examined is provided 

for tests by ISO 13790/2008 (table 4) and takes no account 

of thermal bridges.  

Table 4. Dimensions of construction (ISO13790, 2008) 

Building element Area (m
2

) 

West wall 10,08 

Window glazing 7,00 

North wall 15,40 

South wall 15,40 

East wall 10,08 

Floor 19,80 

Roof-ceiling 19,80 

In order to calculate the influence of the U value in the 

consumption of the primary energy by end use the 

maximum U value (table 1), depending on the climatic zone, 

of all building elements is defined. Then the U value of the 

examined element is changing with a descending step 0.05 

W/m
2

.K while all the other building elements keep their 

original maximum U
 
value. The procedure is carried out for 

all the opaque building elements and for the four climatic 

zones of Greece. Then from the analysis and the linear 

trends of the results, the reduction in the primary energy 

consumption by end use of the building is calculated for a 

reduction of 0.01 W/m
2

.K of the U value of each building 

element and for the four climatic zones. 

2.7. Quantification of the effect of the U value in the life 

cycle of the building element 

In order to quantify the effect of the reduction of U 

value and to import it in the life cycle of each construction 

solution is taken into account the numerical distance of the 

calculated U value
 
of the construction solution from the 

maximum U value of the climatic zone: 

 

 
max calculated

DU U U= −              (3) 

 

where:  �
����������

 – thermal transmittance of the element as 

it is calculated (W/m
2

.K) (Eq. 1); �
���

 – maximum thermal 

transmittance of the element (W/m
2

.K) (table 1). 

Then it is multiplied by the change in the consumption 

of primary energy by end use for a reduction of 0.01 

W/m
2

.K of the U value: 

 

  100%
U

E DU DE= × ×              (4) 

     

where:  �
�

 – the contribution of U value of the element to 

the reduction of annual primary energy consumption by end 

use (kWh/m
2

×year); �� – the numerical distance of the 

maximum and calculated U value of the building element 

(Eq. 3);  �� – the reduction in the primary energy 

consumption by end use of the building for a reduction of 

0.01 W/m
2

.K of the U value.  

This contribution is multiplied by the duration of the 

life cycle of the building elements which was considered to 

be seventy five years. 

 

'  75 
U total U

E E
−

= ×                (5) 
 

where:  �′
�������

 – the contribution of U value of the 

element to the reduction of primary energy consumption by 

end use during the life cycle of the building element 

(kWh/m
2

); �
�

 – the contribution of the U value of the 

element to the reduction of annual primary energy 

consumption by end use (kWh/m
2

×year); 75 – the duration 

of the life cycle of the building element (years).  

 Finally this contribution is converted from kWh/m2 to 
MJ/m

2

 in order to be imported in the life cycle of the 

building element. 

 

'  3.6
U total U total

E E
− −

= ×              (6) 
 
where:  �

�������
 – the contribution of U value of the 

building element to the reduction of primary energy 

consumption by end use during the life cycle of the building 

element (MJ/m
2

);  �′
�������

 – the contribution of U value of 

the building element to the reduction of primary energy 

consumption by end use during its life cycle (kWh/m
2

); 3.6 

– 1.0 kWh equals to 3.6 MJ. 

For each construction solution this contribution is 

imported as a benefit during its life cycle in the sector of 

energy.  It is added with a minus sign to the total energy that 

is required for the stages of the construction and demolition 

of the building element. 

         

final
E            (7) 

 

where:  �
�����

 – the final energy that is imported in the life 

cycle of the building element (MJ/m
2

);  �
����������

 – the 

total energy that is required for the construction and 

demolition of the building element (MJ/m
2

);   �
�������

– the 

contribution of U value of the building element to the 

reduction of primary energy consumption by end use during 

its life cycle of (MJ/m
2

). 

Then the LCA and TOPSIS analysis were carried out 

again with the modified data in the sector of energy. 

3. Results 

3.1. Ideal solutions from the LCA and TOSIS analysis 

– the final energy that is imported in the life 
cycle of the building element (MJ/m2);  

set of TOPSIS analysis for this criterion. However as in the 

first place it was decided to use the weighting set of the 

CML Baseline method, in order to preserve the objectivity 

of this analysis, the use of an extra weight would undermine 

this effort.  

So it was decided to use a typical construction that is 

provided by ISO 13790/2008 for tests, in order to quantify 

the effect of the U value in terms of energy and to be 

imported in the life cycle analysis, without providing an 

extra weight and criterion in the TOPSIS analysis. 

2.6. The influence of U value in the energy performance of 

the building elements  

The software that was used for this analysis is TEE 

KENAK, the software that is used for the inspections of 

energy performance of buildings in Greece. The method that 

is used by the software is the monthly method of energy 

simulations in buildings. For the completeness of this 

analysis it was considered a theoretical heating and cooling 

system according to Regulation of Energy Performance of 

Buildings.  

The typical construction that is examined is provided 

for tests by ISO 13790/2008 (table 4) and takes no account 

of thermal bridges.  

Table 4. Dimensions of construction (ISO13790, 2008) 

Building element Area (m
2

) 

West wall 10,08 

Window glazing 7,00 

North wall 15,40 

South wall 15,40 

East wall 10,08 

Floor 19,80 

Roof-ceiling 19,80 

In order to calculate the influence of the U value in the 

consumption of the primary energy by end use the 

maximum U value (table 1), depending on the climatic zone, 

of all building elements is defined. Then the U value of the 

examined element is changing with a descending step 0.05 

W/m
2

.K while all the other building elements keep their 

original maximum U
 
value. The procedure is carried out for 

all the opaque building elements and for the four climatic 

zones of Greece. Then from the analysis and the linear 

trends of the results, the reduction in the primary energy 

consumption by end use of the building is calculated for a 

reduction of 0.01 W/m
2

.K of the U value of each building 

element and for the four climatic zones. 

2.7. Quantification of the effect of the U value in the life 

cycle of the building element 

In order to quantify the effect of the reduction of U 

value and to import it in the life cycle of each construction 

solution is taken into account the numerical distance of the 

calculated U value
 
of the construction solution from the 

maximum U value of the climatic zone: 

 

 
max calculated

DU U U= −              (3) 

 

where:  �
����������

 – thermal transmittance of the element as 

it is calculated (W/m
2

.K) (Eq. 1); �
���

 – maximum thermal 

transmittance of the element (W/m
2

.K) (table 1). 

Then it is multiplied by the change in the consumption 

of primary energy by end use for a reduction of 0.01 

W/m
2

.K of the U value: 

 

  100%
U

E DU DE= × ×              (4) 

     

where:  �
�

 – the contribution of U value of the element to 

the reduction of annual primary energy consumption by end 

use (kWh/m
2

×year); �� – the numerical distance of the 

maximum and calculated U value of the building element 

(Eq. 3);  �� – the reduction in the primary energy 

consumption by end use of the building for a reduction of 

0.01 W/m
2

.K of the U value.  

This contribution is multiplied by the duration of the 

life cycle of the building elements which was considered to 

be seventy five years. 

 

'  75 
U total U

E E
−

= ×                (5) 
 

where:  �′
�������

 – the contribution of U value of the 

element to the reduction of primary energy consumption by 

end use during the life cycle of the building element 

(kWh/m
2

); �
�

 – the contribution of the U value of the 

element to the reduction of annual primary energy 

consumption by end use (kWh/m
2

×year); 75 – the duration 

of the life cycle of the building element (years).  

 Finally this contribution is converted from kWh/m2 to 
MJ/m

2

 in order to be imported in the life cycle of the 

building element. 

 

'  3.6
U total U total

E E
− −

= ×              (6) 
 
where:  �

�������
 – the contribution of U value of the 

building element to the reduction of primary energy 

consumption by end use during the life cycle of the building 

element (MJ/m
2

);  �′
�������

 – the contribution of U value of 

the building element to the reduction of primary energy 

consumption by end use during its life cycle (kWh/m
2

); 3.6 

– 1.0 kWh equals to 3.6 MJ. 

For each construction solution this contribution is 

imported as a benefit during its life cycle in the sector of 

energy.  It is added with a minus sign to the total energy that 

is required for the stages of the construction and demolition 

of the building element. 

         

 
final calculated U total

E E E
−

= −            (7) 

 

where:  �
�����

 – the final energy that is imported in the life 

cycle of the building element (MJ/m
2

);  �
����������

 – the 

total energy that is required for the construction and 

demolition of the building element (MJ/m
2

);   �
�������

– the 

contribution of U value of the building element to the 

reduction of primary energy consumption by end use during 

its life cycle of (MJ/m
2

). 

Then the LCA and TOPSIS analysis were carried out 

again with the modified data in the sector of energy. 

3. Results 

3.1. Ideal solutions from the LCA and TOSIS analysis 

 – the total 
energy that is required for the construction and demolition 
of the building element (MJ/m2); 

set of TOPSIS analysis for this criterion. However as in the 

first place it was decided to use the weighting set of the 

CML Baseline method, in order to preserve the objectivity 

of this analysis, the use of an extra weight would undermine 

this effort.  

So it was decided to use a typical construction that is 

provided by ISO 13790/2008 for tests, in order to quantify 

the effect of the U value in terms of energy and to be 

imported in the life cycle analysis, without providing an 

extra weight and criterion in the TOPSIS analysis. 

2.6. The influence of U value in the energy performance of 

the building elements  

The software that was used for this analysis is TEE 

KENAK, the software that is used for the inspections of 

energy performance of buildings in Greece. The method that 

is used by the software is the monthly method of energy 

simulations in buildings. For the completeness of this 

analysis it was considered a theoretical heating and cooling 

system according to Regulation of Energy Performance of 

Buildings.  

The typical construction that is examined is provided 

for tests by ISO 13790/2008 (table 4) and takes no account 

of thermal bridges.  

Table 4. Dimensions of construction (ISO13790, 2008) 

Building element Area (m
2

) 

West wall 10,08 

Window glazing 7,00 

North wall 15,40 

South wall 15,40 

East wall 10,08 

Floor 19,80 

Roof-ceiling 19,80 

In order to calculate the influence of the U value in the 

consumption of the primary energy by end use the 

maximum U value (table 1), depending on the climatic zone, 

of all building elements is defined. Then the U value of the 

examined element is changing with a descending step 0.05 

W/m
2

.K while all the other building elements keep their 

original maximum U
 
value. The procedure is carried out for 

all the opaque building elements and for the four climatic 

zones of Greece. Then from the analysis and the linear 

trends of the results, the reduction in the primary energy 

consumption by end use of the building is calculated for a 

reduction of 0.01 W/m
2

.K of the U value of each building 

element and for the four climatic zones. 

2.7. Quantification of the effect of the U value in the life 

cycle of the building element 

In order to quantify the effect of the reduction of U 

value and to import it in the life cycle of each construction 

solution is taken into account the numerical distance of the 

calculated U value
 
of the construction solution from the 

maximum U value of the climatic zone: 

 

 
max calculated

DU U U= −              (3) 

 

where:  �
����������

 – thermal transmittance of the element as 

it is calculated (W/m
2

.K) (Eq. 1); �
���

 – maximum thermal 

transmittance of the element (W/m
2

.K) (table 1). 

Then it is multiplied by the change in the consumption 

of primary energy by end use for a reduction of 0.01 

W/m
2

.K of the U value: 

 

  100%
U

E DU DE= × ×              (4) 

     

where:  �
�

 – the contribution of U value of the element to 

the reduction of annual primary energy consumption by end 

use (kWh/m
2

×year); �� – the numerical distance of the 

maximum and calculated U value of the building element 

(Eq. 3);  �� – the reduction in the primary energy 

consumption by end use of the building for a reduction of 

0.01 W/m
2

.K of the U value.  

This contribution is multiplied by the duration of the 

life cycle of the building elements which was considered to 

be seventy five years. 

 

'  75 
U total U

E E
−

= ×                (5) 
 

where:  �′
�������

 – the contribution of U value of the 

element to the reduction of primary energy consumption by 

end use during the life cycle of the building element 

(kWh/m
2

); �
�

 – the contribution of the U value of the 

element to the reduction of annual primary energy 

consumption by end use (kWh/m
2

×year); 75 – the duration 

of the life cycle of the building element (years).  

 Finally this contribution is converted from kWh/m2 to 
MJ/m

2

 in order to be imported in the life cycle of the 

building element. 

 

'  3.6
U total U total

E E
− −

= ×              (6) 
 
where:  �

�������
 – the contribution of U value of the 

building element to the reduction of primary energy 

consumption by end use during the life cycle of the building 

element (MJ/m
2

);  �′
�������

 – the contribution of U value of 

the building element to the reduction of primary energy 

consumption by end use during its life cycle (kWh/m
2

); 3.6 

– 1.0 kWh equals to 3.6 MJ. 

For each construction solution this contribution is 

imported as a benefit during its life cycle in the sector of 

energy.  It is added with a minus sign to the total energy that 

is required for the stages of the construction and demolition 

of the building element. 

         

 
final calculated U total

E E E
−

= −            (7) 

 

where:  �
�����

 – the final energy that is imported in the life 

cycle of the building element (MJ/m
2

);  �
����������

 – the 

total energy that is required for the construction and 

demolition of the building element (MJ/m
2

);   �
�������

– the 

contribution of U value of the building element to the 

reduction of primary energy consumption by end use during 

its life cycle of (MJ/m
2

). 

Then the LCA and TOPSIS analysis were carried out 

again with the modified data in the sector of energy. 

3. Results 

3.1. Ideal solutions from the LCA and TOSIS analysis 

 – the contribution 
of U value of the building element to the reduction of 
primary energy consumption by end use during its life cycle 
of (MJ/m2).

Then the LCA and TOPSIS analysis were carried out 
again with the modified data in the sector of energy.

3. Results

3.1. Ideal solutions from the LCA and TOSIS analysis
The construction solutions of the building element 

inclined roof show a significant difference as the optimal 
solutions are those with the use of wood than concrete for as 
the main material for its construction (table 5). 

For the same construction solution of inclined roof 
with the only difference the insulating material glass wool 
overrides the use of extruded polystyrene (XPS).

Table 5. Optimal solutions for the building element of sloping roof 

Climatic 
zones

Inclined Roof 

Α
Roof with wood, ceramic tiles and insulation glass 

wool (2 cm)

Β
Roof with wood, ceramic tiles and insulation glass 

wool (2 cm)

Γ
Roof with wood, ceramic tiles and insulation glass 

wool (3 cm)

Δ
Roof with wood, ceramic tiles and insulation glass 

wool (4 cm)

For the construction solutions of masonry in bricks 
the optimal solutions for all climatic zones, with the 
same ranking, are the walls with an air layer (air gap) and 
rock wool for insulation in the middle of the section, the 
ventilated walls with rock wool for insulation in the external 
surface and the masonry with rock wool for insulation in the 
internal surface and final coating with plasterboard (table 6). 

Between the four remaining similar profiles of masonry 
that were examined, with unique variation the insulating 
material, is observed as better solution the use glass wool 
rather than rock wool, expanded polystyrene and extruded 
polystyrene without observed differences between the four 
climatic zones.

Table 6. Optimal solutions for the building element masonry in 
bricks 

Climatic 
zones

Masonry in bricks

Α
Air gap (5 cm) with no contact with the external air 

and insulation rock wool (5 cm) in the middle 

Ventilated wall with insulation rock wool (4 cm) in 
the external surface

Insulation rock wool (4 cm) in the internal surface 
and final covering with plasterboard

Β
Air gap (5 cm) with no contact with the external air 

and insulation rock wool (6 cm) in the middle
Ventilated wall with insulation rock wool (5 cm) in 

the external surface
Insulation rock wool (6 cm) in the internal surface 

and final covering with plasterboard

Γ
Air gap (5 cm)  with no contact with the external air 

and insulation rock wool (7 cm) in the middle
Ventilated wall with insulation rock wool (6 cm) in 

the external surface
Insulation rock wool (6 cm) in the internal surface 

and final covering with plasterboard

Δ
Air gap (5 cm) with no contact with the external air 

and insulation rock wool (7 cm) in the middle
Ventilated wall with insulation rock wool (7 cm) in 

the external surface
Insulation rock wool (7 cm) in the internal surface 

and final covering with plasterboard

Regarding construction solutions of the flat roof 
the inverted roof appears to be better solution than the 
compatible one (table 7).

Table 7. Optimal solutions for the building element flat roof 
Climatic 

zones
Flat roof

Α Inverted flat roof with XPS (6 cm)

Β Inverted flat roof with XPS (7 cm)

Γ Inverted flat roof with XPS (8 cm)

Δ Inverted flat roof with XPS (9 cm)

For the same construction solution of flat roof, with the 
only difference the insulating material, XPS appears to be a 
better solution than polyurethane.

As seen from the results for the building element 
flooring over pilotis a significant contribution to the final 
classification of the sections is the use of wood and then the 
ceramic and marble floor (table 8). 

In construction solutions beam, wall and column of 
reinforced concrete is observed that for all four climatic 
zones as the optimal solution in terms of environmental 
impact appears to be the one with expanded polystyrene 
(table 9, table 10 and table 11). The similarity between 
the results of these building elements can be explained by 
the fact that the differences between them are minor and 
located in small varying in the thickness of the concrete 
and the amount of reinforcing steel that is used for their 
construction.



23

Table 8. Optimal solutions for the building element flooring over 
pilotis

Climatic 
zones

Flooring over pilotis

Α
With external insulation glass wool (4 cm), external 
coating with plasterboard and internal final covering 

with wood

Β
With external insulation glass wool (5 cm), external 
coating with plasterboard and internal final covering 

with wood

Γ
With external insulation glass wool (6 cm), external 
coating with plasterboard and internal final covering 

with wood

Δ
With external insulation glass wool (7 cm), external 
coating with plasterboard and internal final covering 

with wood

Table 9. Optimal solutions for the building element beam of 
reinforced concrete

Climatic 
zones

Beam of reinforced concrete

Α With external insulation EPS (5 cm)
Β With external insulation EPS (6 cm)
Γ With external insulation EPS (7 cm)
Δ With external insulation EPS (8 cm)

Table 10. Optimal solutions for the building element wall of 
reinforced concrete

Climatic 
zones

Wall of reinforced concrete

Α With external insulation EPS (5 cm)
Β With external insulation EPS (6 cm)
Γ With external insulation EPS (7 cm)
Δ With external insulation EPS (8 cm)

Table 11. Optimal solutions for the building element column of 
reinforced concrete

Climatic 
zones

Column of reinforced concrete

Α With external insulation EPS (5 cm)
Β With external insulation EPS (6 cm)
Γ With external insulation EPS (7 cm)
Δ With external insulation EPS (8 cm)

Evaluation
From the results of the LCA and TOPSIS analysis it is 

observed that the use of wood as a material in a construction 
solution is suggested as an optimal solution, according to 
environmental impact, than materials such as concrete (in 
inclined roof) and ceramic or marble (in flooring over pilotis). 
For the horizontal construction solutions of the building 
envelope the use of glass wool is preferred, for the vertical 
construction solutions of reinforced concrete the use of EPS 
and for the masonry in bricks the use of rock wool. The use of 
air gap in the construction solutions appears to have a positive 
contribution in their final ranking as optimal solutions. There 
is no diversity of the ideal construction solutions of the 
building elements between the four climatic zones. In the 
majority of the ideal solutions, as it was expected, the U value 

is higher than the other solutions that have a greater distance 
between the ideal and negative ideal solution. However this 
contradicts with the improved energy performance that these 
not ideal solutions would probably provide in the life cycle of 
a building and will reduce the environmental impacts in terms 
of energy during its life cycle. 

3.2. The influence of the reduction of the U value in the 
energy performance of the building elements

The results in this section are representative of the 
typical construction that was examined in this study.

Fig. 2. Reduction of annual primary energy consumption by end 
use for the change of U value of the building element flooring over 
pilotis for the four climatic zones

As seen from the results of the building element 
flooring over pilotis, the reduction of the U value by  
0.01 W/m2.K, as calculated from the linear trends (Fig. 2), 
leads to a decrease in annual primary energy consumption 
by end use 0.29333 kWh/m2 in climatic zone A, 
0.31967 kWh/m2 in climatic zone B, 0.55 kWh/m2 in 
climatic zone Γ and 0.70643 kWh/m2 in climatic zone Δ.

From the results of the vertical building elements 
(beam, wall, column of reinforced concrete and masonry 
in bricks), the reduction of the U value by 0.01 W/m2.K, 
as calculated from the linear trends (Fig. 3), leads to a 
decrease in annual primary energy consumption by end use 
0.73266 kWh/m2 in climatic zone A, 0.79297 kWh/m2 in 
climatic zone B, 1.3313 kWh/m2 in climatic zone Γ and 
1.7252 kWh/m2 in climatic zone Δ.

Fig. 3. Reduction of annual primary energy consumption by end 
use for the change of U value of the vertical building elements for 
the four climatic zones



24

From the results of building element of roof (inclined 
or flat) the reduction of the U value by 0.01 W/m2.K, as 
calculated from the linear trends (Fig. 4), leads to a 
decrease in annual primary energy consumption by end use 
0.30048 kWh/m2 in climatic zone A, 0.32333 kWh/m2 in 
climatic zone B, 0.50833 kWh/m2 in climatic zone Γ and 
0.67143 kWh/m2 in climatic zone Δ.

Fig. 4. Reduction of annual primary energy consumption by end 
use for the change of U value of building element of roof for the 
four climatic zones

Evaluation

From the results it can be observed that in the 
transaction from climatic zone Α to climatic zone Δ for all 
the building elements the reduction in final annual primary 
energy consumption by end use increases to 100 %–150 %. 
This can be explained from the fact that in this transaction 
the heating requirements of the building increase from zone 
A to Δ and so the influence of the U value to the reduction of 
energy consumption increases.

3.3. The influence of the reduction of the U value in the 
environmental impact of the LCA and the final classification 
of the construction solutions

The results in this section are representative of the 
typical construction that was examined in this study. In this 
analysis the quantification of the distance of the calculated 
U values from the maximum U values was considered in the 
calculation of the environmental impacts. 

In the building elements of masonry in bricks, flat roof, 
inclined roof and flooring over pilotis the ideal solution is 
the same with the results of the first analysis (table 5, table 
6, table 7 and table 8). 

Table 12. Optimal solutions for the building element beam of 
reinforced concrete

Climatic 
zones

Beam of reinforced concrete

Α With external insulation polyurethane (4 cm)
Β With external insulation polyurethane (5 cm)
Γ With external insulation EPS (7 cm)
Δ With external insulation EPS (8 cm)

In construction solutions beam, wall and column of 
reinforced concrete is observed that in climatic zone A and 

B the optimal solution in terms of environmental impact 
appears to be the one with polyurethane (table 12, table 13 
and table 14). In climatic zone Γ and Δ the optimal solution 
appears to be expanded polystyrene (EPS). 

Table 13. Optimal solutions for the building element wall of 
reinforced concrete

Climatic 
zones

Wall of reinforced concrete

Α With external insulation polyurethane (5 cm)
Β With external insulation polyurethane (6 cm)
Γ With external insulation EPS (7 cm)
Δ With external insulation EPS (8 cm)

Table 14. Optimal solutions for the building element column of 
reinforced concrete

Climatic 
zones

Column of reinforced concrete

Α With external insulation polyurethane (4 cm)
Β With external insulation polyurethane (5 cm)
Γ With external insulation EPS (7 cm)
Δ With external insulation EPS (8 cm)

Evaluation
From this analysis is observed that there is more 

diversity in the optimal solutions between the four climatic 
zones. The use of wood instead of materials like concrete, 
ceramics and marble appears to be a better solution as it also 
was in the first analysis. In construction solutions that only 
differ in the type of the insulating material, the one with the 
lower U value appears to be the optimal solution. The use of 
rock wool and air gap in masonry in bricks and glass wool 
in flat roof and flooring over pilotis appear to be optimal 
solutions such as in the first LCA and TOPSIS analysis.

4. Discussion

In this study the LCA takes into account quantities of 
materials that are used for the construction of a building 
element. As a result from the first and second LCA and 
TOPSIS analysis, an important issue that determines an 
ideal construction solution is the number of layers and 
the type of materials that it consists of, as they affect the 
quantities and the environmental impacts of its life cycle.

A second important issue is that the U value affects 
the energy performance of a building and the energy 
consumption by end use. It is a parameter that should be 
considered when a selection of a construction choice 
depends both on the environmental impacts and its energy 
performance during its life cycle. When the construction 
solutions have the same number of layers and materials 
and they only differ in the type of the insulating material 
is suggested that the preferable solution is the one with the 
lower U value. 

The use of wood as material is an optimal solution, 
when the criteria for this choice are environmental impacts, 
as in some categories of environmental impacts it has nearly 
zero or maybe negative values.



25

The use of air gap in construction is suggested either 
if the air layer is isolated in the middle of the construction 
or in a ventilated solution because it improves the energy 
performance of a building element by decreasing the U 
value without increasing the environmental impacts.

5. Conclusions

Continuous efforts in Europe aim to reduce the 
environmental impact from the energy consumption and 
to decrease the use of non renewable sources of energy. 
This occurs from the fact that in a life cycle of buildings 
the majority of environmental impacts come from the 
energy consumption from the use stage of the building. The 
environmental impact from the materials and the other stages 
amount a small percentage of the total environmental impact 
of its life cycle. However even it is a small percentage it is 
something that cannot be ignored. All these interventions 
for upgrading the energy performance of a building should 
be examined for their environmental impacts. Also in the 
choice of the materials and the construction solutions for 
upgrading an existing building or designing a new one, 
should be taken into account the environmental impact 
during their whole life cycle and not only in the operation 
stage. 

Furthermore in the choice of an insulating material or 
a construction solution that affects the energy performance 
of a building should be considered not only the U value that 
it provides but also if the benefit from this choice overrides 
the environmental impacts during its life cycle.

This study shows the optimal construction solutions 
of building elements in residential buildings in Greece and 
provides suggestions for the materials that should be used. 
Its aim is to provide a helpful guide to the designers in order 
to choose a construction solution, depending on the climatic 
zone that is going to be constructed, considering its energy 
performance and its environmental impact during its life 
cycle. 

In conclusion this study shows that the influence of the 
U value in the energy performance of the building elements 
and the choice of the insulating material are significant 
factors to the environmental impacts of their life cycle. 
For the masonry in bricks the use of rock wool with the 
use of air gap is suggested rather than EPS or XPS in all 
climatic zones. In the construction solution of flat roof the 
use of XPS appears to be an optimal solution in all climatic 
zones rather than polyurethane. For the inclined roof the 
use of wood and glass wool appear to be optimal solutions 
rather than concrete and EPS in all climatic zones. In the 
construction solution of flooring over pilotis the use of glass 
wool is suggested rather than XPS in all climatic zones. For 
the vertical construction solutions of reinforced concrete 
(beam, column and wall) the use of polyurethane in climatic 
zones A and B is suggested rather than EPS and XPS. In 
climatic zones Γ and Δ the use of EPS appear to be an 
optimal solution rather than polyurethane and XPS. 

Acknowledgment

This study was carried out for a diploma thesis in the 
MSc program “Environmental Protection and Sustainable 

Development” of the Department of Civil Engineering 
of Aristotle University of Thessaloniki. This paper was 
completed as a part of this MSc program and co-financed 
by the Act “Scholarships program SSF (State Scholarships 
Foundation/IKY) with an individualized assessment process 
of the academic year 2012-2013” from resources of the 
Operational Program “Education and Lifelong Learning”, 
of the European Social Fund (ESF) and the NSRF (2007-
2013).

References

CML, 2013. Available at: http://cml.leiden.edu/software/data-
cmlia.html (accessed 15 August 2013).

Eurostat, 2013. Available at: epp.eurostat.ec.europa.eu/: http://epp.
eurostat.ec.europa.eu/tgm/table.do?tab=table&init=1&plug
in=1&language=en&pcode=ten00086 (accessed 25 August 
2013).

Hellenic Statistical Authority (EL.STAT.), 2013. Available at: 
http://www.statistics.gr/portal/page/portal/ESYE/PAGE-
themes?p_param=A1302 (accessed 23 June 2013).

ISO13790,  2008. Energy performance of buildings - Calculation 
of energy use for space heating and cooling.

ΚΕΝΑΚ, 2010. Αριθ. Δ6/Β/οικ. 5825 ΄Εγκριση Κανονισμού 
Ενεργειακής Απόδοσης Κτιρίων Εφημερίς της Κυβερνήσεως 
της Ελληνικής Δημοκρατίας, 5333-5356, [Regulation of 
Energy Performance in Buildings].

Preconsultants, 2008. Available at: http://www.pre-sustainability.
com/simapro-7-database-and-methods-library (accessed 15 
August 2013).

Αραϊλόπουλος, Α., Χαστάς, Π. (2009). Ανάλυση κύκλου ζωής 
στα κτίρια με εφαρμογή του λογισμικού Simapro και της 
μεθόδου eco-indicator 99. Πολυτεχνική Σχολή Α.Π.Θ, 
Πολιτικών Μηχανικών, Θεσσαλονίκη [Arailopoulos  A., 
Chastas P. -  Life Cycle Assessment in Buildings with the use 
of the software SimaPro and the method eco-indicator 99].

ΤΟΤΕΕ 20701−1, 2010. Αναλυτικές εθνικές προδιαγραφές 
παραμέτρων για τον υπολογισμό της ενεργειακής απόδοσης 
κτιρίων και την έκδοση του πιστοποιητικού ενεργειακής 
απόδοσης. Εφημερίς της Κυβερνήσεως της Ελληνικής 
Δημοκρατίας, Vol. 1387, 21435-21442. [Technical 
instructions of the Technical Chamber of Greece- Detailed 
national standards and parameters for calculating the energy 
performance of buildings and issuing energy performance 
certificate].

ΤΟΤΕΕ 20701−2, 2010. Θερμοφυσικές ιδιότητες δομικών υλικών 
και έλεγχος της θερμομονωτικής επάρκειας των κτιρίων. 
Εφημερίς της Κυβερνήσεως της Ελληνικής Δημοκρατίας, 
Vol. 1387, 21435-21442. [Technical instructions of the 
Technical Chamber of Greece- Thermophysical properties 
of building materials and control of thermal insulation 
efficiency of buildings].

ΤΟΤΕΕ 20701−3, 2010. Κλιματικά δεδομένα ελληνικών περιοχών. 
Εφημερίς της Κυβερνήσεως της Ελληνικής Δημοκρατίας 
Vol. 1387, 21435-21442. [Technical instructions of the 
Technical Chamber of Greece - Climate data of Greek 
regions].

Received 2013 12 16 
Accepted after revision 2014 02 08



26

Dimitrios BIKAS – Professor, Director Laboratory of Building Construction and Building Physics, Vice chairman of the 
Dept. of Civil Engineering. 
Main research area: Building construction, Building Physics, Energy efficiency of buildings, Sustainable building.
Address: Aristotle University of Thessaloniki, Dept. of Civil Engineering, Laboratory of Building Construction and 

Building Physics, 54124 Thessaloniki, Greece.
Tel.: +30 2310 995763, +30 6972096311
E-mail: bikasd@civil.auth.gr 

Panagiotis CHASTAS – Civil engineer and MSc “Environmental protection and sustainable development” graduate, Dept. 
of Civil Engineering of Aristotle University of Thessaloniki (AUTH).
Main research area: Life Cycle Analysis and energy performance in residential buildings.
Address:  Aristotle University of Thessaloniki, Dept. of Civil Engineering, Laboratory of Building Construction and 

Building Physics, 54124 Thessaloniki, Greece.
Tel.: +30 6976500057
E-mail: pchastas@civil.auth.gr