Thermal rehabilitation of buildings facades with exterior
insulation systems
Bruno André Pirão Freire
Extended Abstract
Supervisor: Prof. António Heleno Domingues Moret Rodrigues
June 2015
Thermal rehabilitation of buildings facades with exterior insulation systems
Extended Abstract
1
1. Introduction
In the early of the XXI century, residential and services buildings sectors were responsible for 40% of
final energy consumption in the European Union, which led to the introduction of legislation to ensure
that they gradually consume less energy. In that way, the European Commission published Directive
2002/91/EC [1] related to energy performance of buildings (EPBD - Energy Performance of Buildings
Directive), with the main objective to adopt: (i) a methodology of calculation of the integrated energy
performance of buildings; (ii) minimum requirements on the energy performance of new buildings and
large existing buildings that are subject to major renovation; (iii) energy certification of buildings; (iv) the
regular inspection of boilers and of air conditioning systems. In 2010, this directive was recast by
Directive 2010/31/EU (EPBD recast) [2], which aims to strengthen those previous provisions and
implement new measures to ensure the following objectives in 2020: 20% reduction in emissions of
greenhouse gas effect; increase by 20% the renewable energy production and; 20% increase in energy
efficiency. In addition to improve the objectives previously defined by Directive 2002/91/EC, this
reformulation introduced an approach for calculating cost-optimal levels of minimum requirements for
the energy performance of new and existing buildings that are present in the Commission Delegated
Regulation (EU) Nº244/2012 [3]. This approach is based on a comparative methodology related to
climatic conditions, investment costs, maintenance and operating costs (including energy costs and
savings, the category of building concerned, earnings from energy produced), where applicable, and
disposal costs, where applicable. As a result of reduction in the number of new buildings and the
expansion potential of the rehabilitation of existing buildings in Portugal [4], is intended to perform an
analysis of the performance of some external thermal insulation composite systems (ETICS), since they
have potential to improve the thermal and energy performance of existing buildings. This analysis will
be based on a case study building in Lisbon through dynamic simulation of its thermal and energy
behaviour, generated by EnergyPlus software, and subsequent application of European methodology
for calculating cost-optimal levels associated with each of the ETICS systems under study.
2. Case study definition
The case study is defined by a building in need of thermal rehabilitation and built before the first
regulation about building thermal performance characteristics (RCCTE) [5]. The chosen case study is
an entire floor of a residential building with 10 floors, built in 1967, with four apartments per floor and
four outer facades (Figure 1). This will allow a performance analysis according to the cardinal points
because each apartment is directed to each of the cardinal points (North, South, East and West). In
addition, there are two similar buildings in the adjacent plots (Figure 2), which allow the possibility of
repeat the building rehabilitation strategy. In this case, the building in study is located in Lisbon area,
more precisely in Olivais neighbourhood, and is integrated into winter climate zone I1 and summer
climate zone V2, according to the current regulation [6] (Figure 3). The energy performance analysis of
the chosen floor and apartments will be realized before thermal rehabilitation, preserving the original
exterior walls construction characteristics, and after thermal rehabilitation, which will be tested with
various ETICS solutions according to the different solar orientations.
Thermal rehabilitation of buildings facades with exterior insulation systems
Extended Abstract
2
2.1. Geometry
The chosen floor of the building has four apartments, each one with three bedrooms, called AP01-E
AP02-N, AP03-O and AP04-S, which solar orientations are East, North, West and South, respectively
(Figure 4). All apartments are symmetric and each one has 74.13m2 of floor area and a ceiling height of
2.8m. The opaque facade of each apartment occupies approximately 77% of outside area and the
remaining 23% are glazing.
Figure 4 - Floor plan and three-dimensional modeling of the case study floor.
2.2. Building elements characterization
About the building facade is assumed two facades solutions before the building thermal rehabilitation.
One of them is composed by the existing solution of double masonry brick wall with air gap between
them and without thermal insulation (SO1) and the other solution is composed by a single masonry brick
wall (SO2), which is a solution that exists in many buildings built before the first RCCTE. The present
study will focus on the performance of ETICS solutions in rehabilitation applied only to exterior walls,
since the remaining construction elements (glazing, interior walls, floors and ceilings) will maintain its
original constitution and will not be implemented any rehabilitation solution in these elements. In that
way, Table 1 shows the heat transfer coefficients of different construction elements that will be part of
the dynamic simulations in order to analyze the building energy performance.
Table 1 - Heat transfer coefficients of existent construction elements. Exterior walls
Interior walls Floors and
ceilings Glazing
SO1 SO2
U (W/m2.ºC) 1.09 1.39 1.75 2.41 5.74
Figure 1 - Building exterior perspective.
Figure 2 - Building location. Figure 3 - Winter and summer climate zoning for case study [6].
AP01-E AP03-O
AP04-S
AP02-N
Thermal rehabilitation of buildings facades with exterior insulation systems
Extended Abstract
3
2.3. Characterization of rehabilitation solutions with ETICS
The following simulations of thermal rehabilitation of facades with ETICS will show different types of
insulation applied to these systems such as expanded polystyrene (EPS), extruded polystyrene (XPS),
mineral wool (MW) and insulation cork board (ICB). These rehabilitation solutions will be applied with
thermal insulation thicknesses of 20, 40, 60, 80 and 100mm to each of the original solutions (SO1 and
SO2). Table 2 presents the heat transfer coefficients of each thermal rehabilitation solutions applied in
the original solutions.
Table 2 - Heat transfer coefficients of rehabilitation solutions with ETICS to each of original solutions.
3. Energy needs
The purpose of this section is to calculate nominal energy needs per m2 in heating and cooling seasons
to each of the original solutions and thermal rehabilitation with ETICS solutions. The calculation of these
energy needs is made by modeling the building floor chosen, with all the definitions described above,
and perform a dynamic simulation with EnergyPlus software. In that way, is intended to compare the
results of the original solutions SO1 and SO2 to respective rehabilitation solutions. The weather file used
for the dynamic simulation was the Lisbon weather data [7] and the heating season length was defined
in 5.3 months and the cooling season length in 4 months (June, July, August and September). Heating
and cooling set-points are assumed to be 18ºC and 25ºC, respectively and according to the thermal
regulation [6].
3.1. Usage patterns
For energy needs simulation, internal gains were defined by the number of occupants living daily in each
apartment, lighting and equipments. The current energy performance regulation for residential buildings
[6] establishes a permanent average value of 4W/m2 for internal gains without considering specific
usage patterns but, in this simulation, internal gains were calculated from a daily usage patterns for an
increase approach between the simulation and reality [8] (Figure 5). The average number of occupants
per m2, the average of annual energy consumption for lighting and equipments in residential buildings
are defined according to the survey Inquérito ao Consumo de Energia no Sector Doméstico 2010 [9].
For ventilation, it is assumed that takes place equally in all fractions and without mechanical systems.
The ventilation rate was determined through simplified criteria of previous regulation (RCCTE),
assuming that the case study has unrated windows/doors frames for air permeability, windows blind box
SO1
Exterior double
wall
Thick. (mm) 20 40 60 80 100 20 40 60 80 100 20 40 60 80 100 20 40 60 80 100
U (W/m2.ºC) 0.70 0.52 0.41 0.34 0.29 0.68 0.50 0.39 0.32 0.28 0.70 0.52 0.41 0.34 0.29 0.73 0.55 0.44 0.37 0.32
SO2
Exterior single
wall
Thick. (mm) 20 40 60 80 100 20 40 60 80 100 20 40 60 80 100 20 40 60 80 100
U (W/m2.ºC) 0.82 0.58 0.45 0.37 0.31 0.79 0.55 0.43 0.35 0.29 0.82 0.58 0.45 0.37 0.31 0.86 0.62 0.49 0.40 0.34
ETICS with expanded polystyrene ETICS with extruded polystyrene ETICS with mineral wool ETICS with insulation cork board
SO1 EPS SO1 XPS SO1 MW SO1 ICB
SO2 EPS SO2 XPS SO2 MW SO2 ICB
Thermal rehabilitation of buildings facades with exterior insulation systems
Extended Abstract
4
and the absence of air intake devices in the facade. Table 3 presents the usage patterns, lighting and
equipment power and the rate of air renewal.
Table 3 - Internal gains usage patterns and air
renewal rate [9].
Figure 5 - Internal gains usage patterns through
the day.
Heating and cooling equipments will also work only when the occupants are at home, which makes its
operation restricted to the schedule from 18h to 8h.
For the calculation of the energy needs for cooling season it is assumed the use of shading devices
(exterior shutters of plastic rulers) that are activated when the incident solar radiation on the glazing
exceeds 300W/m2, although this option is disabled for heating season.
3.2. Energy needs in heating season
Figure 6 presents the energy needs in kWh/m2 in heating season for each apartment, with the original
solution SO1 and respective rehabilitation solutions with ETICS.
Figure 6 - Energy needs for heating in all apartments for SO1 and rehabilitation solutions with ETICS.
The annual energy savings in relation to SO1 solution ranges, on average, between 11% and 25%, for
thicknesses of 20mm and 100mm respectively, and for the apartment with more energy needs in heating
Occupation (number of occupants) 3
Occupation period
Every day from 18h to 8h (activity period from
18h to 24h and from 7h to 8h; sleeping
period from 24h to 7h)
Total daily gain (Wh/m2) 51
Average power per hour (W/m2) 2.13
Lighting Every day from 18h to 24h
Consumption per hour (Wh) 149
Daily consumption per m2 (Wh/m
2) 8.35
Average power per hour (W/m2) 0.35
Equipment
Every day 24 hours (usage pattern 1: from
24h to 7am; usage pattern 2: from 7h to
18h; usage pattern 3: from 18h to 24h)
Daily consumption per m2 (Wh/m
2) 46
Average power per hour (W/m2) 1.92
Daily internal gains per m2 (Wh/m
2) 105
Average internal gains per hour (W/m2) 4.40
Hourly air renewal rate (Rph) 1.05
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
Po
we
r (W
/m2)
Hours of the day (h)
Occupants Equipment Lighting
0
2
4
6
8
10
12
14
16
18
20
22
24
AP01-E AP02-N AP03-O AP04-S
En
erg
y n
ee
ds
(k
Wh
/m2)
Apartments
SO1
SO1EPS20
SO1EPS40
SO1EPS60
SO1EPS80
SO1EPS100
SO1XPS20
SO1XPS40
SO1XPS60
SO1XPS80
SO1XPS100
SO1MW20
SO1MW40
SO1MW60
SO1MW80
SO1MW100
SO1ICB20
SO1ICB40
SO1ICB60
SO1ICB80
SO1ICB100
Thermal rehabilitation of buildings facades with exterior insulation systems
Extended Abstract
5
season (AP02-N). For the apartment with lower energy needs in heating season (AP04-S), the annual
savings is located on average between 12% and 27% for thicknesses of 20mm and 100mm respectively.
With regard to the SO2 solution (Figure 7), energy savings for the apartment with more energy needs
in heating season (AP02-N) ranges on average between 14% and 29% to 20mm and 100mm
thicknesses respectively. For the apartment with lower energy needs in heating season (AP04-S),
annual savings are located on average between 16% and 32% for 20mm and 100mm thicknesses
respectively.
Figure 7 - Energy needs for heating in all apartments for SO2 and rehabilitation solutions with ETICS.
3.3. Energy needs in cooling season
Figures 8 and 9 presents energy needs for cooling season relative to SO1, SO2 and respective
rehabilitation solutions with ETICS. As can be seen, the largest energy savings in this season takes
place in AP01-E and AP04-S apartments, which have higher energy needs during this period. For the
other two apartments, AP02-N and AP03-O, the reduction in energy needs with rehabilitation solutions
is relatively low and there are no wide variations between energy needs of different rehabilitation
solutions with differents thicknesses. In these figures it is also concluded that rehabilitation solutions
with ETICS are less effective in decreasing energy needs in cooling season compared to heating season.
Figure 8 - Energy needs for cooling in all apartments for SO1 and rehabilitation solutions with ETICS.
0
2
4
6
8
10
12
14
16
18
20
22
24
26
AP01-E AP02-N AP03-O AP04-S
En
erg
y n
ee
ds
(k
Wh
/m2)
Apartments
SO2
SO2EPS20
SO2EPS40
SO2EPS60
SO2EPS80
SO2EPS100
SO2XPS20
SO2XPS40
SO2XPS60
SO2XPS80
SO2XPS100
SO2MW20
SO2MW40
SO2MW60
SO2MW80
SO2MW100
SO2ICB20
SO2ICB40
SO2ICB60
SO2ICB80
SO2ICB100
0
1
2
3
4
5
6
7
8
9
10
AP01-E AP02-N AP03-O AP04-S
En
erg
y n
ee
ds
(k
Wh
/m2)
Apartments
SO1
SO1EPS20
SO1EPS40
SO1EPS60
SO1EPS80
SO1EPS100
SO1XPS20
SO1XPS40
SO1XPS60
SO1XPS80
SO1XPS100
SO1MW20
SO1MW40
SO1MW60
SO1MW80
SO1MW100
SO1ICB20
SO1ICB40
SO1ICB60
SO1ICB80
SO1ICB100
Thermal rehabilitation of buildings facades with exterior insulation systems
Extended Abstract
6
Figure 9 – Energy needs for cooling in all apartments for SO2 and rehabilitation solutions with ETICS.
4. Cost-optimal analysis
As mentioned above, EPBD 2010 provides that Member States shall ensure implementations with the
minimum requirements related to energy performance in order to achieve cost-optimal levels [2], [3].
The optimal cost is obtained from the global costs associated with the improved energy performance
measures for a period of 30 years. The global cost of a rehabilitation solution is given by the sum of
construction costs, which take place in the year when project starts, with the deferred costs in time, for
a calculation period of 30 years, related to energy (heating and cooling) necessary to ensure the indoor
thermal comfort, and maintenance work to ensure the performance quality of the solution during the
period established. The global cost (𝐶𝑔) is obtained by the following expression [3]:
,
1
, )()( fd
i
iaIg ViRCCC
(1)
where means the calculation period; 𝐶𝐼 means initial investment cost for measure of energy efficiency;
𝑅𝑑(𝑖) means discount factor for year i; 𝑉𝑓,𝜏 means residual value of measure at the end of the calculation
period (discounted to the starting year 𝜏0) and 𝐶𝑎,𝑖 means annual cost during year i for measure of
energy efficiency as [3]:
𝐶𝑎,𝑖 = 𝐶𝑒,𝑖 + 𝐶𝑚,𝑖 (2)
where 𝐶𝑒,𝑖 means energy cost for year i and 𝐶𝑚,𝑖 means maintenance cost of rehabilitation solution for
year i. The discount factor 𝑅𝑑(𝑖) is obtained based on discount rate r, which is defined as 3%, and
according with the following expression [3]:
𝑅𝑑(𝑖) = (
1
1 + 𝑟/100)𝑖
(3)
where (𝑖) means the number of years from the starting períod.
0
1
2
3
4
5
6
7
8
9
10
AP01-E AP02-N AP03-O AP04-S
En
erg
y n
ee
ds
(k
Wh
/m2)
Apartments
SO2
SO2EPS20
SO2EPS40
SO2EPS60
SO2EPS80
SO2EPS100
SO2XPS20
SO2XPS40
SO2XPS60
SO2XPS80
SO2XPS100
SO2MW20
SO2MW40
SO2MW60
SO2MW80
SO2MW100
SO2ICB20
SO2ICB40
SO2ICB60
SO2ICB80
SO2ICB100
Thermal rehabilitation of buildings facades with exterior insulation systems
Extended Abstract
7
To calculate the energy costs for a period of 30 years, were obtained the annual heating and cooling
energy needs for the case study and the different rehabilitation solutions applied (Table 2). It is possible
to calculate the final energy (annual) from the ratio between energy needs (from heating and cooling)
and energy efficiency EER/COP of HVAC equipments for heating and cooling. Assuming that all the
apartments in study have the same type of air conditioning system, corresponding to thermal production
units of air conditioning systems with efficiency class C, is obtained, for systems with split units,
multissplit and VRF, a minimum EER of 2.80 and a minimum COP of 3.20 [6]. From the calculation of
the annual final energy is obtained the primary energy through the conversion factor of energy used (2.5
in case of electricity). Then, the results were normalized by the floor area of the case study. The price
of electricity for the calculation was analyzed from a simple tariff of low voltage, higher than 3.45 kVA
and lower than 6.9 kVA, and the value used was 0.1497€/kWh based on reference prices of liberalized
electricity market published by ERSE for 2014 and for the tariff "EDP Comercial Casa" [10]. This price
was updated according to European Commission forecast for energy prices and respective interest rate
[11]. Maintenance costs used for each ETICS solutions correspond to a ten-year period costs according
to CYPE Gerador de Preços [12]. For construction costs were considered the cost of the material used
and his installation, for each rehabilitation measures adopted [13].
In Figures 10, 11 and 12 are presented cost-optimal graphs for different rehabilitation solutions with
ETICS compared to the original solutions SO1 and SO2. In each graph is indicated the insulation
thickness value considered optimum for each rehabilitation solution.
Figure 10 – Cost-optimal graphs for SO1 and rehabilitation solutions with ETICS, for the apartments
AP01-E and AP02-N.
SO1
SO1EPS40
SO1XPS40
SO1MW40
SO1ICB20
26
28
30
32
34
36
38
40
42
44
46
50 52 54 56 58 60 62 64 66
Glo
ba
l co
st
pe
r flo
or
are
a (
€/m
2)
Primary energy kWh/(m2.ano)
AP01-E
SO1 SO1EPS SO1XPS
SO1MW SO1ICB
SO1
SO1EPS60
SO1XPS40
SO1MW40
SO1ICB40
26
28
30
32
34
36
38
40
42
44
60 62 64 66 68 70 72 74 76 78 80
Glo
ba
l co
st
pe
r flo
or
are
a (
€/m
2)
Primary energy kWh/(m2.ano)
AP02-N
SO1 SO1EPS SO1XPS
SO1MW SO1ICB
Thermal rehabilitation of buildings facades with exterior insulation systems
Extended Abstract
8
Figure 11 – Cost-optimal graphs for SO1 and rehabilitation solutions with ETICS, for the apartments
AP03-O and AP04-S.
Figure 12 - Cost-optimal graphs for SO2 and rehabilitation solutions with ETICS, for the apartments
AP01-E, AP02-N, AP03-O and AP04-S.
SO1SO1EPS40
SO1XPS40
SO1MW40
SO1ICB20
25
27
29
31
33
35
37
39
41
43
45
42 44 46 48 50 52 54 56 58
Glo
ba
l co
st
pe
r flo
or
are
a (
€/m
2)
Primary energy kWh/(m2.ano)
AP03-O
SO1 SO1EPS SO1XPS
SO1MW SO1ICB
SO1
SO1EPS40
SO1XPS20
SO1MW20
SO1ICB20
22
25
28
31
34
37
40
43
46
35 40 45 50
Glo
ba
l co
st
pe
r flo
or
are
a (
€/m
2)
Primaty energy kWh/(m2.ano)
AP04-S
SO1 SO1EPS SO1XPS
SO1MW SO1ICB
SO2
SO2EPS40
SO2XPS40
SO2MW40
SO2ICB40
24
26
28
30
32
34
36
38
40
42
44
48 51 54 57 60 63 66 69 72
Glo
ba
l co
st
pe
r flo
or
are
a (
€/m
2)
Primary energy kWh/(m2.ano)
AP01-E
SO2 SO2EPS SO2XPS
SO2MW SO2ICB
SO2
SO2EPS60
SO2XPS60
SO2MW40
SO2ICB40
24
26
28
30
32
34
36
38
40
42
60 62 64 66 68 70 72 74 76 78 80 82 84
Glo
ba
l co
st
pe
r flo
or
are
a (
€/m
2)
Primary energy kWh/(m2.ano)
AP02-N
SO2 SO2EPS SO2XPS
SO2MW SO2ICB
SO2SO2EPS40
SO2XPS40
SO2MW40
SO2ICB40
24
26
28
30
32
34
36
38
40
42
44
42 44 46 48 50 52 54 56 58 60 62 64
Glo
ba
l co
st
pe
r flo
or
are
a (
€/m
2)
Primary energy kWh/(m2.ano)
AP03-O
SO2 SO2EPS SO2XPS
SO2MW SO2ICB
SO2
SO2EPS40
SO2XPS40
SO2MW40
SO2ICB20
21
23
25
27
29
31
33
35
37
39
41
43
45
35 37 39 41 43 45 47 49 51 53 55
Glo
ba
l co
st
pe
r flo
or
are
a (
€/m
2)
Primary energy kWh/(m2.ano)
AP04-S
SO2 SO2EPS SO2XPS
SO2MW SO2ICB
Thermal rehabilitation of buildings facades with exterior insulation systems
Extended Abstract
9
5. Conclusions
According to the cost-optimal graphics it is concluded that, for SO1 solution, only apartments oriented
to east and north (AP01-E and AP02-N) may benefit from savings, from a financial point of view, through
rehabilitation solutions with ETICS. In case of apartment AP01-E, only ETICS solution with EPS is below
the SO1 reference value with a cost-optimal corresponding to 40mm insulation thickness (SO1EPS40).
In AP02-N apartment, ETICS solutions with EPS, XPS and MW are those producing savings compared
to the original solution with the cost-optimal situated in 60mm thickness in case of EPS (SO1EPS60)
and 40mm thickness in case of XPS (SO1XPS40) and MW (SO1MW40). In the other apartments,
oriented to west and south (AP03-O and AP04-S), all presented rehabilitation solutions are above the
reference value for original solution SO1.
For SO2 solution, the conclusion is similar to SO1 solution where only apartments oriented to east and
north (AP01-E and AP02-N) benefit from rehabilitation ETICS solutions, establishing savings from a
financial point of view and for a period of 30 years. The difference between them is that in SO2 solution,
and for AP01-E apartment, rehabilitation solutions with EPS and XPS are beneficial and, for AP02-N
apartment, all rehabilitation solutions with ETICS analyzed (with EPS, XPS, MW and ICB) are below the
reference value of SO2 solution. In case of AP01-E apartment, the cost-optimal was obtained from
ETICS with EPS and XPS solutions with 40mm insulation thickness (SO2EPS40 and SO2XPS40). For
AP02-N apartment, cost-optimal was defined, in case of EPS and XPS with 60mm thickness
(SO2EPS60 and SO2XPS60) and for MW and ICB solutions was set to 40mm insulation thickness
(SO2MW40 and SO2ICB40). In the others apartments, AP03-O and AP04-S, none of the rehabilitation
solutions with ETICS obtained a value lower than the original solution SO2.
With these results it is concluded that rehabilitation solutions with ETICS systems applied to this
particular building are more effective in apartments with highest energy needs for heating, having this
heating season an important weight in calculation of primary energy. It is also expected that the
progressive increase of air conditioning systems efficiency and the reduction of reference comfort
temperature (from 20°C in the previous legislation to 18°C in the current regulation), give rise a reduction
of benefits from rehabilitation measures with ETICS, from a financial point of view, and may influence
the choice of the type of insulation to be implemented.
6. References
[1] Comissão Europeia, “Directiva 2002/91/CE do Parlamento Europeu e do Conselho de 16 de
Dezembro de 2002 relativa ao desempenho energético dos edifícios,” Jornal Oficial das
Comunidades Europeias, p. 7, 2002.
[2] Comissão Europeia, “Directiva 2010/31/UE do Parlamento Europeu e do Conselho de 19 de Maio
de 2010 relativa ao desempenho energético dos edifícios,” Jornal Oficial da União Europeia, p.
23, 2010.
Thermal rehabilitation of buildings facades with exterior insulation systems
Extended Abstract
10
[3] Comissão Europeia, “Regulamento Delegado (UE) N.º 244/2012 da Comissão de 16 de Janeiro
de 2012 que complementa a Diretiva 2010/31/UE do Parlamento Europeu e do Conselho,” Jornal
Oficial da União Europeia, p. 19, 2012.
[4] Instituto Nacional de Estatística, Estatísticas da Construção e Habitação 2010, Lisboa: Instituto
Nacional de Estatística, 2011, p. 93.
[5] Ministério das Obras Públicas, Transportes e Comunicações, “Decreto-Lei nº 40/90 de 6 de
Fevereiro, Regulamento das Características do Comportamento Térmico dos Edifícios, RCCTE,”
Diário da República - 1ª Série, p. 15, 1990.
[6] Ministério da Economia e do Emprego, “Decreto-Lei nº 118/2013 de 20 de Agosto de 2013,
Regulamento de Desempenho Energético dos Edifícios de Habitação, REH,” Diário da República
- 1ª Série, p. 18, 2013.
[7] INETI, “Lisbon weather file,” 2014. [Online]. Available:
http://apps1.eere.energy.gov/buildings/energyplus/cfm/weather_data3.cfm/region=6_europe_wm
o_region_6/country=PRT/cname=Portugal. [Acedido em 2 Junho 2014].
[8] N. Pereira, Energy-Efficient Retrofit of Residential Buildings, Lisbon 1960's - 70's case study,
Lisboa: Intituto Superior Técnico, 2012, pp. 252-257.
[9] INE e DGEG, Inquérito ao Consumo de Energia no Sector Doméstico 2010, Lisboa: Instituto
Nacional de Estatística e Direcção-Geral de Energia e Geologia, 2011, p. 117.
[10] INE; DGEG, “Inquérito ao Consumo de Energia no Sector Doméstico 2010,” Instituto Nacional de
Estatística e Direcção-Geral de Energia e Geologia, Lisboa, 2011.
[11] ERSE, Entidade Reguladora dos Serviços Energéticos, “Preços de referência no mercado
liberalizado de energia elétrica e gás natural em Portugal Continental,” Agosto 2014. [Online].
Available: http://www.erse.pt/pt/Simuladores/Documents/Pre%C3%A7osRef_BTN.pdf. [Acedido
em 20 Setembro 2014].
[12] European Commission, EU Energy, Transport and GHG Emissions, Trends to 2050, Reference
Scenario 2013, Luxembourg: Publications Office of the European Union, 2014, pp. 47-53.
[13] CYPE Ingenieros, S.A., “Gerador de preços,” 2014. [Online]. Available:
http://www.geradordeprecos.info/. [Acedido em 29 Setembro 2014].
[14] Saint-Gobain Weber Portugal, S.A., “Simulador de Cálculo,” 2014. [Online]. Available:
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