Report on technical and social feasibility studies

Transcription

1 Promotion of smart and integrated NZEB revation measures in the European revation market (NeZeR) Contract N : IEE/13/763/ SI Report on technical and social feasibility studies Date: Lead contractor: ISPE

2 NeZeR Report on technical and social feasibility studies Page 2 of 58 Disclaimer The sole responsibility for the content of this presentation lies with the authors. It does t necessarily reflect the opinion of the European Union. Neither the EACI r the European Commission are responsible for any use that may be made of the information contained therein. Table of contents 1 Introduction Finland National legislation framework Reference building Traditional building revation More ambitious building revation - NZEBR Ecomic data in analyzed revation alternatives Estimative investment costs Annual costs Technical and social feasibility study of the NZEBR Alternative The Netherlands National legislation framework Reference building Traditional building revation More ambitious building revation - NZEBR Ecomic data in analyzed revation alternatives Estimative investment costs Annual costs Technical and social feasibility study of the NZEBR Alternative Romania National legislation framework Reference building Traditional building revation More ambitious building revation NZEBR Ecomic data in analyzed revation alternatives Estimative investment costs Annual costs Technical and social feasibility study of the NZEBR Alternative Spain National legislation framework Reference building Traditional building revation More ambitious building revation - NZEBR Ecomic data in analyzed alternatives Estimative investment costs Annual costs Technical and social feasibility study of the NZEBR alternative Sweden National legislation framework Reference building... 41

3 NeZeR Report on technical and social feasibility studies Page 3 of Traditional building revation More ambitious building revation - NZEBR Ecomical data in analyzed alternatives Estimative investment costs Annual costs Technical and social feasibility study of the NZEBR Alternative Energy savings Societal benefits Conclusions References... 58

4 NeZeR Report on technical and social feasibility studies Page 4 of 58 1 INTRODUCTION The IEE NeZeR project promotes the implementation and smart integration of Nearly Zero Energy Building Revation (NZEBR) measures and the deployment of Renewable Energy Sources (RES) in the European revation market. The best available techlogies achieving NZEBR have been reported in NeZeR report Technical solutions for energy reduced and renewable energy sources for optimal energy efficient revation. In order to achieve the NZEBR potential in partner cities there is also a need to estimate and analyse the technical aspects and social issues regarding NZEBR implementation. The purpose of this document is to show the advantages of NZEBR over traditional revation alternative from technical and social point of views in the partner countries. Main technical indicators of these two revation alternatives for the selected reference buildings have been calculated and analysed. The technical and social feasibility study evaluates and analyses the potential to achieve NZEBR and deploy RES in the partner cities for the identified residential typologies and the related social aspects. The feasibility study is focused on the NZEBR revation as the traditional revation is supposed to be rather standard and low-risk. The presented results will be used as input for creating NZEBR Action Plans for each city partner.

5 NeZeR Report on technical and social feasibility studies Page 5 of 58 2 FINLAND 2.1 National legislation framework Since the Finnish building code requires improvements in energy efficiency when a building is refurbished. Three options for energy efficiency improvement targets exist: Building element specific requirements: In case that building elements are replaced/revated (e.g. base floor, windows, doors) the thermal resistance must reach the same level as the building code for new buildings requires. Decreasing energy consumption: The energy consumption per square meter should be decreased. Energy efficiency class (E-luku): The energy efficiency class (considering both energy consumption and the energy source) should be decreased to the required level. The regulation is very flexible and exceptions can be made in case of technical, functional or ecomic reasons, in case that the energy efficiency improvements are t possible / feasible. It is also t necessary to make the improvements at once but the measures can be implemented in stages, during a longer time frame. The heating energy and electrical energy use of Finnish residential and public buildings is responsible for about 30 % of the Finnish CO 2 emissions. Building revation measures such as supplementary insulation, heat recovery from outlet air and RES deployment, can be implemented to reduce the buildings energy use and CO 2 emissions. These measures are set for each revation alternative aiming to achieve optimal building comfort level with minimal consumption of conventional energy. 2.2 Reference building The reference building is located in the climate zone of Southern Finland with average yearly temperature of 4-5 C (summer 14.8 C and winter -3 C). The reference building is t an existing building but the energy simulations for the case building have been made according to the building standards of the 1970s and considering the climate zone of Southern Finland. The Finnish the housing stock comprises 2.8 million dwellings of which as much as 44% are apartments located in block of flats. A relatively large housing stock was built in the 1950s, 60s and 70s. The share of this housing of the total housing stock is 43%. This building category is interesting from revation business point of view t only because of volume but also their revation need. Furthermore, considering their age, their poor energy performance and their deterioration, it is evident that largescale revation activities are needed. A five-floor multi-family building built in the 1970s was chosen as the reference building. The main technical characteristics and elements of energy building performance are presented in table 1.

6 NeZeR Report on technical and social feasibility studies Page 6 of 58 Table 1 Reference building data in Finland Specification Definition Unit Value Number of apartments apart. 29 Roof type flat roof Total heated space area m Total heated living space volume m Total building volume m Heating source District heating DHW source District heating Electricity source Power grid Onsite RES: solar panels PV panels biomass source geothermal Source heat pump Ventilation yes Heat recovery Shading system Heating period - days 365 Lighting type Incandescent external walls W/m 2 K 0.6 Building elements (average U-value): windows W/m 2 K 2.79 roof W/m 2 K 0.39 base floor W/m 2 K 0.48 Heating kwh/m 2 y 130 Specific energy consumptions DHW kwh/m 2 y 51 Electricity kwh/m 2 y 44 Heating MWh/y 241 Annual energy consumption DHW MWh/y 94 Electricity MWh/y Traditional building revation The traditional revation of the reference building includes the following measures for increase the building energy performance: Building envelope exterior walls: old outer layer and old insulation material removed, new insulation by 245 mm is fixed on an inner layer and new outer concrete with ceramic tile installed; roof: old roof mastics and insulation removal and new insulation by 340 mm and bew asphalt mastic cover installed; base floor: additional external insulation windows: renewal of windows, balcony doors and front doors changing the existing double pane windows to quadruple pane windows. Lighting system modernization of lighting type by changing from incandescent to ecomic system. Table 2 presents the new building energy performance after implementation of the traditional revation measures.

7 NeZeR Report on technical and social feasibility studies Page 7 of 58 Table 2 Building data after traditional revation in Finland Specification Definition Unit Value Heating source District heating DHW source District heating Electricity source Power grid Onsite RES: solar panels PV panels biomass source geothermal source heat pump Ventilation yes Heat recovery Shading system Heating period - days 365 Lighting type ecomic external walls W/m 2 K 0.14 Building elements (average U-value) windows W/m 2 K 0.7 roof W/m 2 K 0.10 base floor W/m 2 K 0.15 Heating kwh/m 2 y 50 Specific energy consumptions DHW kwh/m 2 y 51 Electricity kwh/m 2 y 30 Heating MWh/y 93 Annual energy consumption DHW MWh/y 94 Electricity MWh/y 55 -electricity MWh/y 55 *conventional source MWh/y 55 Energy supplied *RES MWh/y - -heat MWh/y 187 *conventional source MWh/y 187 *RES MWh/y - Figure 1 Building energy consumption: Reference building vs. Traditional revation (Finland)

8 NeZeR Report on technical and social feasibility studies Page 8 of More ambitious building revation - NZEBR The more ambitious building revation (NZEBR) alternative proposes major revation measures for increasing the insulation and air tightness of building and RES deployment in order to meet the NZEB criteria. NZEBR includes the following main measures: Building envelope exterior walls: old outer layer and old insulation material removed, new insulation by 410 mm is fixed on an inner layer and new outer concrete with ceramic tile installed; roof: old roof mastics and insulation removal and new insulation by 460 mm and bew asphalt mastic cover installed; base floor: additional external insulation. windows: renewal of windows, balcony doors and front doors changing the existing double pane windows to quadruple pane windows; Lighting system modernization of lighting type by changing from incandescent to ecomic system; Onsite RES solar heat collectors on the roof m 2 ; PV panels on the roof m 2. Table 3 presents the new building energy performance after implementation of the NZEBR measures. Table 3 Building data after NZEBR in Finland Specification Definition Unit Value Heating source District heating+exhaust air heat pump DHW source District heating + exhaust air heat pump Electricity source Power grid + PV panels Onsite RES: solar panels PV panels yes biomass source geothermal source Heat pump yes Ventilation yes Heat recovery Shading system Heating period days 365 Lighting type ecomic external walls W/m 2 K Building elements (average U-value): windows W/m 2 K 0.7 roof W/m 2 K floor slab W/m 2 K 0.15 Specific energy consumptions Heating kwh/m 2 y 19 DHW kwh/m 2 y 10

9 NeZeR Report on technical and social feasibility studies Page 9 of 58 Specification Definition Unit Value Electricity kwh/m 2 y 35 Heating MWh/y 35 Annual energy consumption DHW MWh/y 19 Electricity MWh/y 65 -electricity MWh/y 85 *conventional source MWh/y 65 Energy supplied *RES MWh/y 20 -heat MWh/y 185 *conventional source MWh/y 54 *RES MWh/y 110 Figure 2 Building energy consumption: Reference building vs. NZEBR (Finland) 2.5 Ecomic data in analyzed revation alternatives Estimative investment costs The estimative investment costs of revation measures in both alternatives are shown in table 4 below: Table 4 Estimative investment costs for achieving the building revation in Finland Specification Unit Value (excluding VAT) Traditional revation Euro 532,000 NZEBR Euro 702,900

10 NeZeR Report on technical and social feasibility studies Page 10 of Annual costs The estimative values of annual costs corresponding to each building revation alternatives and actual situation are presented in table 5. These costs include the all expenses for managing, operating, maintaining and repairing the building, such as: Energy costs (fuels, heat, electricity); Auxiliary costs (water, sewage, domestic waste, etc); Personnel costs (personnel working in connection with building operation, maintenance and management); Maintenance and repair costs Other annual operating costs. These values do t contain any amortization costs corresponding to the new investments for building revation. Table 5 Annual costs in Finland Specification Unit Value Reference building Euro/year 28,500 Traditional revation Euro/year 18,900 NZEBR Euro/year 13, Technical and social feasibility study of the NZEBR Alternative In Finland, 65% of all apartments are privately owned while about 12% are rental apartments owned by institutional owners (built with interest subsidy loan or ARA loan) and 17.5% are other rental apartments 1. Housing companies with private owners can receive loans for financing their revation activities from banks. Some support mechanisms are available: The Housing Finance and Development Centre of Finland, ARA, provides interest subsidy for housing company loans (maximum 40-50% of the refurbishment costs). 2 ARA also provides subsidies for assessments of building condition, in case that the building has undergone water damage or is causing health problems. 3 Also revating companies are offering relatively affordable funding instruments. In case of small house revations it is possible to get taxation decreases connected to share of revation labor costs. In rental apartments which are privately financed, rent may increase even more than 15% in case that extensive revation activities are carried out, which increase the value of the apartment (in other cases, rent increase cant exceed 15% per year). It 1 Statistics Finland, Housing. 2 Rönty & Paiho, Rahoitusratkaisuja asuinrakennusten perusparannuksiin ja energiakorjauksiin. VTT Techlogy Taloyhtiö.net.,

11 NeZeR Report on technical and social feasibility studies Page 11 of 58 has to be indicated in the rental agreement if the rent will be increased and what is the basis for the increase (such as consumer good index). In apartments built with interest subsidy loans rent increases cant be implemented as freely because these rents are based on the building maintenance expenses. However, rent can be increased if the rising expenses demand it (also in case of modernization), and in this case the tenant need to be informed maximum two months in advance. 4 In case of major revation activities, the tenant also needs to be informed at least 6 months in advance. The tenant has the right to decreased rent in case that it is t possible to live in the apartment during the revation works. 5 In case of rental apartments, tenants might benefit from the revation in case that indoor environment (thermal comfort, acoustics etc.) of the apartment improves. The owner-occupiers of apartments might benefit from the revation in terms of improved indoor environment (as well as tenants). Other benefits that revation might offer are the decreased maintenance costs because of the decreased heating expenses. Also the value of the building will probably increase, especially if the aesthetics of the building improves, which will benefit the apartment owner when the apartment is sold. Table 6 Overall assessment of technical & social feasibility for NZEBR in Finland NZEBR Impact on living space and measure other social aspects Proven techlogy (score 1-5) Possible technical risks in revation or with respect to the energy performance Overall assessment of technical feasibility (1=low risk, 5= high risk) Overall assessment of social feasibility (1=low risk, 5= high risk) Measure 1: Additional insulation in exterior walls 5 In case of exterior wall insulation the thickness of the walls usually increases and this will cause some effects to the windows and would change a architecture of the building. In most cases the residents need to move out from the building for the duration of the revation and therefore seeking for temporary housing poses challenges. 2 2 Moisture risks must be avoided by thorough moisture planning and protection. All structures damaged by moisture must be drained or renewed. In some cases revation is possible to organize so, that the residents are able to live in their departments during the revation. Insulation of the external wall will cause better temperature condition in the departments. In marginal cases which lead to moisture problems there may be even severe health problems to inhabitants

12 NeZeR Report on technical and social feasibility studies Page 12 of 58 NZEBR measure Proven techlogy (score 1-5) Possible technical risks in revation or with respect to the energy performance Impact on living space and other social aspects Overall assessment of technical feasibility (1=low risk, 5= high risk) Overall assessment of social feasibility (1=low risk, 5= high risk) Measure 2: Additional external insulation in exterior roof 5 Exterior insulation of the roof will cause changes on the architecture of the building. In block houses the benefits of the roof insulation is t as high as other energy revations Revation causes moderate harm for residents. Insulation of the roof will cause better thermal conditions in upper floor of the building. 1 2 Measure 3: Additional internal insulation of external roof 5 Internal insulation is t possible to make in most of the buildings with flat roof. In block houses the benefits of the roof insulation is t as high as other energy revations. Revation causes moderate harm for residents. Insulation of the roof will cause better thermal conditions in upper floor of the building. 1 2 Moisture risks must be avoided by thorough moisture planning and protection. All structures damaged by moisture must be drained or renewed. In marginal cases which lead to moisture problems there may be even severe health problems to inhabitants. Measure 4: Additional external insulation in floor 5 Adding insulation to the base floor might be challenging depending on the case building. If subfloor space exists, adding insulation is rather difficult if the room height should t decrease, because then the floor and old insulation need to be teared down. In case that a subfloor space exists, insulation can be added from below. In most cases revation causes moderate harm for residents. Insulation of the floor will cause better thermal conditions in lower floor of the building. 1 2 Measure 5: Windows, triple glazing and gas 5 When the energy efficiency of an old building with natural ventilation is improved with additional insulation and new more efficient windows, also the ventilation system needs to be revated in order to ensure good indoor air quality by clean supply air. If the air tightness of an old building is improved but the ventilation system is t revated, it might cause indoor air problems to the residents. 1 2 Measure 6: PV panels 4 Timing has a central role in the feasibility of a PV system. As most of solar electricity is New system has effect on the living quality, but it causes savings in energy 2 3

13 NeZeR Report on technical and social feasibility studies Page 13 of 58 NZEBR measure Proven techlogy (score 1-5) Possible technical risks in revation or with respect to the energy performance Impact on living space and other social aspects Overall assessment of technical feasibility (1=low risk, 5= high risk) Overall assessment of social feasibility (1=low risk, 5= high risk) generated (during daytime) when the demand is low. Therefore new techlogies such as efficient storage systems as well as political support in form of feed-in tariffs are important. costs. PV panels may increase fire load. Measure 7: Solar heat collectors 4 The ecomic benefits of the solar heat collectors vary depending of the other heating system of the building (energy cost of district heating is much lower than electrical heating). New system has effect on the living quality, but it causes savings in energy costs. 2 3 Measure 8: Exhaust air heat pump 3 Exhaust air heat pump significantly decreases the purchased heating energy but simultaneously it increases the electricity consumption substantially and therefore the overall energy cost might t decrease as much as supposed. Installation of the exhaust air heat pump is relatively simple and it will t cause harm for residents. New system has effect on the living quality, but it causes savings in energy costs. 1 3 Exhaust air heat pumps are t yet widely used in block houses, so the long-term experiences are missing. Measure 9: Ground source heat pump 4 The ecomic benefits of the ground source heat pump varies depending of the existing heating system of the building (energy cost of district heating is much lower than electrical heating). Installation of the ground source heat pump is t a large scale revation. Drilling the needed holes will cause some harm. New system has effect on the living quality, but it causes savings in energy costs. 1 3 Measure 10: ESX ventilation with preheating 5 Risk is that in typical Finnish block house the totally new air conditioning channels have to be built and that may cause construction defects. In most cases the residents need to move out from the building during the revation. However, the revation of the ventilation system will improve the air quality in the departments. 1 3

14 NeZeR Report on technical and social feasibility studies Page 14 of 58 3 THE NETHERLANDS 3.1 National legislation framework There is a national covenant between important national stakeholders ( Energieakkoord ) which outlines the ambition to reach a net-zero energy building stock by To realise this it has been agreed that for the residential sector: existing buildings: until 2020 some dwellings will be revated in such a way that their energy label improves with at least two steps (e.g. from E to C); new buildings: Near Zero Energy Buildings by 2020 (and already from 2018 for government buildings) in conformity with the EPBD; in the rental housing sector: on average label B for social housing and at least label C for 80% of the private rental sector. For the n-residential building sector the existing legislation should be applied which prescribes that all energy efficiency measures with a pay-back time of 5 years or less are implemented. As from July 2013 the National Building Code prescribes that for a large revation (i.e. if >25% of the building envelope is renewed) the U value of the façades, floors and roof should be at least 0.27 W/m 2.K 6. The windows and doors that are renewed should have U-value of at least 1,65 W/m 2.K. However, for traditional revations this requirement usually does t apply because less than 25% of the envelope is renewed. There are special prescriptions from the building code with regard to renewable energy systems. 3.2 Reference building The selected building type can be found in almost every town or city in the Netherlands, especially in the larger cities, like Amsterdam, Rotterdam, The Hague, Utrecht. They are also common in smaller towns with inhabitants. The selected apartment buildings with outside walkways ( galerijflats in Dutch) were built in the period from about 1960 onwards. We give below the data for the buildings build specifically in the period , as they are found very frequently in the Netherlands and are quite representative of a large collection of multifamily buildings which are the mination for revation, with the aim to improve overall building quality and energy performance in particular. The building characteristics and energy performance data were derived from the official publication Typical Buildings 2011 Existing buildings, Agentschap NL, 2011 There are about of such dwellings in the Netherlands which corresponds to 2,4% of the total residential building stock. The majority is rented, 73% in the social sector, 11% private rental sector and 16% privately owned. 6 Actually, an R c -value of 3,5 W/m2.K is prescribed. Including the standard transfer resistance of 0.17 W/m2.K for an exposed building element this gives a U value of 1/( )=0.27 W/m 2.K for facades and roofs

15 NeZeR Report on technical and social feasibility studies Page 15 of 58 Figure 3 Reference building in the Netherlands The multi-family buildings chosen as Dutch representative buildings were built between 1965 and 1974 and have 5-12 floors with apartments. The main technical characteristics and elements of the Dutch reference building are presented in table 7. Table 7 Reference building data in the Netherlands Specification Definition Unit Value Number of apartments apart. 50 Roof type flat roof Total heated space area m Total heated living space volume m Total building volume m Heating source Collective heating boiler (gas fired) Heat source for DHW preparing Collective heating boiler (gas fired) Electricity source Power grid Onsite RES Solar panels PV panels Biomass source Geothermal Source Heat pump Ventilation Heat recovery Shading system Heating period - days 250 Lighting type fluorescent external walls W/m 2 K 1.7 windows W/m / K Building elements (average U-value): roof W/m 2 K 1.0 floor slab W/m 2 K 2.3 Heating kwh/m 2 y 117 Specific energy consumptions DHW kwh/m 2 y 63 Electricity kwh/m 2 y 37 Heating MWh/y Annual energy consumption DHW MWh/y Electricity MWh/y double glass / single glass

16 NeZeR Report on technical and social feasibility studies Page 16 of 58 Specification Definition Unit Value -electricity MWh/y *conventional source MWh/y Energy supplied *RES MWh/y 0 -heat MWh/y 738 *conventional source MWh/y 738 *RES MWh/y Traditional building revation For traditional revation we assume that a revation to Energy label B is done by the following measures: Building envelope exterior walls: façade insulation (wall cavity filling or inside insulation); windows: replacing glass with coated double glass with good U-value. Heating system replacing the collective heating and hot water supply by individual high efficiency boilers. Table 8 presents the main data resulted after implementation of the traditional building revation measures. Table 8 Building data after traditional revation in the Netherlands Specification Definition Unit Value Heating source individual high-efficiency gas boiler Heat source for DHW preparing individual high- efficiency gas boiler Electricity source Power grid Onsite RES: solar panels PV panels biomass source geothermal source heat pump Ventilation yes Heat recovery Heating period - days 250 Lighting type CFLs external walls W/m 2 K 0.37 Building elements (average U-value): windows W/m 2 K 1.65 roof W/m 2 K 0.27 floor slab W/m 2 K 0.3 Heating kwh/m 2 y 39 Specific energy demand DHW kwh/m 2 y 31 Electricity kwh/m 2 y 43 Heating MWh/y Annual energy consumption DHW MWh/y Electricity MWh/y electricity MWh/y *conventional source MWh/y Energy supplied *RES MWh/y 0 -heat MWh/y 287 *conventional source MWh/y 287 *RES MWh/y 0

17 NeZeR Report on technical and social feasibility studies Page 17 of 58 Figure 4 Building energy consumption: Reference building vs. Traditional revation (the Netherlands) 3.4 More ambitious building revation - NZEBR The NZEB-level revation assumes the following measures: Building envelope exterior walls: façade insulation - Rc=3.5 m² K/W roof: insulation - Rc = 5 m² K/W ground floor: insulation - Rc = 3.5 m² K/W windows: triple glass windows with high thermal resistance frames and closed balconies (single glass) Ventilation system mechanical ventilation with high efficiency heat recovery Heating & DHW system All electric building, gas supply Space heating and DHW with heat pump on ground water Onsite RES PV panels 15 m 2 /2250 Wp per dwelling Solar panels 2 m 2 per dwelling Heat pump for heating and DHW consumers Lighting system and other electric equipment LED lighting in common spaces 10% saving on domestic electricity consumption by providing energy efficient equipment (fridge, tv, LED lighting).

18 NeZeR Report on technical and social feasibility studies Page 18 of 58 Table 9 presents the indicators of new building energy performance after implementation of the NZEBR measures. Table 9 Building data after NZEBR in the Netherlands Specification Definition Unit Value Heating source Heat pump ground water source Heat source for DHW preparing Heat pump ground water source Electricity source Power grid + PV system onsite Onsite RES: Solar panels yes PV panels yes biomass source geothermal source Heat pump yes Ventilation yes Heat recovery yes Shading system Heating period - days 250 Lighting type LED external walls W/m 2 K 0.27 Building elements (average U-value): windows W/m 2 K 1.0 roof W/m 2 K 0.19 floor slab W/m 2 K 0.27 Heating kwh/m 2 y 2 Specific energy demand DHW kwh/m 2 y 7 Electricity kwh/m 2 y 38 Heating MWh/y 8.2 Annual energy consumption DHW MWh/y 28.7 Electricity MWh/y electricity MWh/y *conventional source MWh/y Energy supplied *RES MWh/y heat MWh/y 0 *conventional source MWh/y 0 *RES MWh/y 0

19 NeZeR Report on technical and social feasibility studies Page 19 of 58 Figure 5 Building energy consumption: Reference building vs. NZEBR (the Netherlands) 3.5 Ecomic data in analyzed revation alternatives Estimative investment costs The estimative investment costs of revation measures in both alternatives are shown in table 10 below: Table 10 Estimative investment costs for achieving the building revation in the Netherlands Specification Unit Value (withoutvat) Traditional revation Euro 300,000 NZEBR Euro 1,250, Annual costs The estimative values of annual costs corresponding to each building revation alternative and actual situation are presented in table 11. These costs include the all expenses for managing, operating, maintaining and repairing the building, such as: Energy costs (fuels, heat, electricity); Auxiliary costs (water, sewage, domestic waste, etc); Personnel costs (personnel working in connection with building operation, maintenance and management); Maintenance and repair costs Other annual operating costs. These values don t contain any amortization costs corresponding to the new investments for building revation.

20 NeZeR Report on technical and social feasibility studies Page 20 of 58 Table 11 Annual costs in the Netherlands Specification Unit Value Reference building Euro/y Traditional revation Euro/y NZEBR Euro/y Technical and social feasibility study of the NZEBR Alternative Financial aspects More than 80% of the houses of the reference type are rental houses and most of these are owned by social housing companies (75%). Only a small share is owned by private owner- residents (15%). This means that the revation will mostly be an investment from the social housing company. The rent of the houses may be increased after revation but this rent increase also means that the housing company will need to get the approval of more 70% of the existing tenants. In practice this requirement can be a significant stumbling block because part of the residents is opposed to rent increases. If the revation is executed tenants will benefit from the reduced energy costs. The reduction of energy costs should be equal or bigger than the rent increase. Also the thermal comfort and indoor air quality of the houses will improve very much. Under new legislation for zero energy revations the housing company may offer the tenants an energy bundle contract where the cold rent and energy cost are added into a single lump sum which is settled in a long term contract and collected by the housing company. In this way the problem of split incentive (i.e. house owner makes the investments but the tenant receives the benefits) can be solved. In case of private owners in these buildings the financing will be much more difficult as income of residents will often be rather low. However, special energy loans with easier conditions and lower interest are available for the purpose of energy efficient revations. Also it is often quite difficult to reach an agreement among private owners on a collective revation investment. Technical and social aspects Table 12 gives an overview of the different technical measures that are needed along with an assessment of their technical and social aspects.

21 NeZeR Report on technical and social feasibility studies Page 21 of 58 Table 12 Overall assessment of technical & social feasibility for NZEBR in the Netherlands NZEBR Impact on living space and measure other social aspects Proven techlogy (score 1-5) Possible technical risks in revation or with respect to the energy performance Overall assessment of technical feasibility (1=low risk, 5= high risk) Overall assessment of social feasibility (1=low risk, 5= high risk) External insulation of walls and roof (D ) 4-proven techlogy but some risks remaining thermal bridges (i.e. at gallery and balconies) may compromise insulation value and may cause local condensation impact on internal space, but exterior is changed drastically low impact on residents, need to leave house 2 1 Triple glass windows (D ) 3- proven techlogy but t so much experience among Dutch builders Added weight of windows and thickness may be problem; Possibility of overheating at south facing windows, sun screens may be necessary resident will need to leave house for short time, exposure to weather for short period 2 2 Closed balconies 4-proven techlogy but some risks Possibility of overheating at south facing balconies, sun screens may be necessary little impact 1 1 Energy performance may be compromised if balcony is used as extra living area Mechanic al ventilation with heat recovery (D ) 3- proven techlogy but practical implementati on may be difficult installation of air ducts may be difficult; Risk of poor installation of ducts, resulting in ise problems Energy performance may be compromised if windows are opened frequently. Loss of interior space due to ducts and ventilation unit; Risk of extra ise from ducts and motor; Better indoor air quality due to filters in city centres/heavy traffic; Lower indoor humidity and smaller risk of condensation and fungi; Maintenance requirements of air filters; 3 3 General public distrust of HR ventilation techlogy, risk of people shutting the system down

22 NeZeR Report on technical and social feasibility studies Page 22 of 58 NZEBR measure Proven techlogy (score 1-5) Possible technical risks in revation or with respect to the energy performance Impact on living space and other social aspects Overall assessment of technical feasibility (1=low risk, 5= high risk) Overall assessment of social feasibility (1=low risk, 5= high risk) Heat pump and undergrou nd heat storage (D ) 3- proven techlogy but practical implementati on may be difficult Low temp floor/wall heating is necessary but may be difficult to implement. Underground t always suitable for heat storage Less radiative heat, Slow response of heating Floor will usually be higher than beforehand People need to move all furniture out of house Energy performance may be compromised due to poor maintenance and monitoring Better thermal comfort and less particles in the air: good for CARA patients PV panels on roof (D ) 5 proven techlogy Shading loss due to chimneys and antenna s on roof ne 1 1 Solar thermal panels (D or 6.4) 5 proven techlogy Heat losses in hot water distribution ne 2 1 LED lighting in common spaces 5 proven techlogy ne Risk of poorer light quality: color and spreading 1 2 efficient electrical household equipment 5 proven techlogy ne leasing or rental construction necessary for equipment 1 2 In conclusion some of the key measures may be technically difficult to implement and are t possible in every building. A correct execution by the builder is essential and this can be a barrier for successful implementation. There are also significant social implications especially from HR ventilation systems. A good understanding of the system by the user is needed to help prevent using the system wrong or shutting it down, e.g. by a good manual. On the other hand, the envelope insulation measures are t very difficult to implement and deliver quite good improvements as well.

23 NeZeR Report on technical and social feasibility studies Page 23 of 58 4 ROMANIA 4.1 National legislation framework The Ministry of Regional Development and Public Administration carries out, as appropriate in thermal rehabilitation of buildings. In this area, the MRDPA initiates, finances and / or manages / implements, under the law, development programmes and projects of national, regional and local interest. The main legislation documents are: Low. 372/ regarding the energy performance of buildings (last version according to low. 159/2013) which transposed the Directive 2010/31/UE; Order. 157/2007 approving the technical regulation Methodology for calculating energy performance of buildings (the last version according to Orders. 1071/2009, 1217/2010 and 2210/2013) contains: Part I Building envelope; Part II Technical system; Part III Energy audit and Building Energy Performance Certificate Part IV - Calculation abstract of the energy performance of buildings and apartments and Model of the apartment energy performance certificate The national programme on the thermal rehabilitation of multi-family building is made based on the Emergency Ordinance. 18/2009 on increasing the energy performance of multi-family buildings. This document provides for the intervention works to be carried out for the thermal insulation of the residential multi-family buildings built between 1950 and 1990, the stages required for the performance of the works, the method of their funding as well as for the obligations and responsibilities pertaining to public administration authorities and the owners associations. The intervention works to be carried out shall be: - the thermal insulation of the exterior walls; - the replacement of the existing windows and external doors, including the joinery designed for access to the residential block, with energy performance joinery; - the hydrothermal insulation of the terrace/the thermal insulation of the floor over the last level, where there is a roof framing; - the thermal insulation of the floor over the underground, where the block was designed to include apartments on the ground floor; - works for the dismantling of the installations and equipments mounted visibly on the façades/terrace of the residential block and their reassembling after the thermal insulation works have been completed; - works for the recovery of the envelope finishes.

24 NeZeR Report on technical and social feasibility studies Page 24 of 58 These intervention works shall be carried out with a view to enhancing the energy performance of residential multi-family buildings so as to determine a decrease in the specific annual energy consumption calculated for heating below 100 kwh/m 2 of the useful area under conditions of ecomic efficiency. In 2013, MRDPA issued first version of Plan for increasing the number of nearly zero energy buildings in Romania containing the background elements. This document provides a proposal of NZEB definition, taking into consideration the building type, destination (residential, administrative) and climatic area, separately for new and existent buildings. This plan is only at the study level. 4.2 Reference building The reference building is located in Timisoara, at 571 km from the capital city of Bucharest. Timisoara is the largest city in Western Romania and the second most important city of the country. It is the capital of Timis County and of the Western Region of Romania and has an influence area of 5,000 km 2, the second largest in the country. In the field of increasing the building energy performance, Timi oara Municipality has identified as major goal of the SEAP , the revation works to transform the existing buildings into energy efficient buildings. Timi oara is divided into 13 districts, with many of 23,000 residential buildings, both individual and multi-family building types. According to the recent data, there are dwellings, mainly of them are placed in multi-family buildings. At the same as the national level, the most residential buildings were constructed in the latter half of the 20th century, with the period standing out as the most significant construction time, as illustrated in figure below. Figure 6 Age profil of residential bulding stock in Romania (source: More than 97% of the total dwellings from Timi oara are private ownership. Concerning to the level of the energy consumption, it was registered in 2008 the final energy consumption by 1.8 TWh corresponding to dwellings. This consumption has as main energy sources: electricity, natural gas, district heating and biomass (figure 7)

25 NeZeR Report on technical and social feasibility studies Page 25 of 58 5% 12% 35% Electricity District heating Natural gas Biomass (firewood) 48% Figure 7 Energy consumption of residential buildings located in Timi oara at the 2008 level. (source: The reference building represents a multi-family building with ten floors located in Timi oara, constructed in Figure 8 Reference building in Romania (Timi oara) Table 13 Reference building data in Romania Specification Definition Unit Value Number of apartments apart. 40 Roof type flat roof - terrace Total heated space area m Total heated living space volume m Total building volume m Heating source District heating DHW source District heating Electricity source Power grid Onsite RES: solar panels PV panels biomass source geothermal source heat pump Ventilation Heat recovery

26 NeZeR Report on technical and social feasibility studies Page 26 of 58 Specification Definition Unit Value Shading system Heating period - days 217 Lighting type incandescent external walls W/m 2 K 1.83 Building elements (average U-value): windows W/m 2 K 2.56 roof W/m 2 K 0.91 floor slab W/m 2 K 2.41 Heating kwh/m 2 y 177 Specific energy consumptions DHW kwh/m 2 y 15 Electricity kwh/m 2 y 21 Heating MWh/y Annual energy consumption DHW MWh/y 47 Electricity MWh/y electricity MWh/y 65.8 *conventional source MWh/y 65.8 Energy supplied *RES MWh/y 0 -heat MWh/y *conventional source MWh/y *RES MWh/y Traditional building revation The main energy efficiency measures included in the traditional building revation alternative are presented taking into consideration the different technical system of the building. Building envelope exterior walls: new thermal insulation 100 mm EPS; roof: new thermal insulation 80 mm XPS; floor slab: new thermal insulation 50 mm EPS; windows: double glazing with PVC frame. Lighting system new low-energy lighting system In table 14 are presented the main building data resulted after implementation of the traditional building revation measures. Table 14 Building data after traditional revation in Romania Specification Definition Unit Value Heating source District heating DHW source District heating Electricity source Power grid Onsite RES: solar panels PV panels biomass source geothermal source heat pump Ventilation Heat recovery Shading system Heating period - days 217 Lighting type ecomic Building elements (average U-value): external walls W/m 2 K 0.557

27 NeZeR Report on technical and social feasibility studies Page 27 of 58 Specification Definition Unit Value windows W/m 2 K roof W/m 2 K floor slab W/m 2 K Heating kwh/m 2 y 100 Specific energy demand DHW kwh/m 2 y 15 Electricity kwh/m 2 y 8 Heating MWh/y Annual energy consumption DHW MWh/y 47 Electricity MWh/y electricity MWh/y 25.1 *conventional source MWh/y 25.1 Energy supplied *RES MWh/y 0 -heat MWh/y *conventional source MWh/y *RES MWh/y 0 Figure 9 Building energy consumption: Reference building vs. Traditional revation (Romania) 4.4 More ambitious building revation NZEBR In this revation alternative the following energy efficiency measures are proposed for the each technical system of the building: Building envelope external walls: new thermal insulation 300 mm EPS; roof: new thermal insulation 80 mm XPS; floor slab: new thermal insulation 50 mm EPS; windows: triple low-e glazing with PVC frame. Ventilation system mechanical ventilation with heat recovery system

28 NeZeR Report on technical and social feasibility studies Page 28 of 58 Lighting system new low-energy lighting system Onsite RES 25 thermal solar panels installed on the roof 40 PVs installed on the roof In table 15 are presented the main building data resulted after implementation of the NZEBR measures. Table 15 Building data after NZEBR in Romania Specification Definition Unit Value Heating source District heating DHW source District heating + Thermal solar panels Electricity source Power grid + PV panels Onsite RES: solar panels yes PV panels yes biomass source geothermal source heat pump Ventilation yes Heat recovery yes Shading system Heating period - days 217 Lighting type ecomic external walls W/m 2 K Building elements (average U-value): windows W/m 2 K roof W/m 2 K floor slab W/m 2 K Heating kwh/m 2 y 63 Specific energy demand DHW kwh/m 2 y 15 Electricity kwh/m 2 y 8 Heating MWh/y Annual energy consumption DHW MWh/y 47 Electricity MWh/y electricity MWh/y 25.1 *conventional source MWh/y 16.3 Energy supplied *RES MWh/y 8.8 -heat MWh/y *conventional source MWh/y *RES MWh/y 47

29 NeZeR Report on technical and social feasibility studies Page 29 of 58 Figure 10 Building energy consumption: Reference building vs. NZEBR (Romania) 4.5 Ecomic data in analyzed revation alternatives Estimative investment costs The estimative investment costs of revation measures in both alternatives are shown in table 16 below: Table 16 Estimative investment costs for achieving the building revation in Romania Specification Unit Value (without VAT) Traditional revation Euro 179,840 NZEBR Euro 588, Annual costs The estimative values of annual costs corresponding to each building revation alternative and actual situation are presented in table 17. These costs include the all expenses for managing, operating, maintaining and repairing the building, such as: Energy costs (fuels, heat, electricity); Auxiliary costs (water, sewage, domestic waste, etc); Personnel costs (personnel working in connection with building operation, maintenance and management); Maintenance and repair costs Other annual operating costs. These values don t contain any amortization costs corresponding to the new investments for building revation.

30 NeZeR Report on technical and social feasibility studies Page 30 of 58 Table 17 Annual costs in Romania Specification Unit Value Reference building Euro/y 41,241 Traditional revation Euro/y 26,568 NZEBR Euro/y 29, Technical and social feasibility study of the NZEBR Alternative In Romania, private ownership is the dominant form of tenure accounting for 98.8% of the total residential dwellings stock, 54.2% are placed in urban area. More than 90% of these total residential dwellings were built before 1989 when the elements for increasing the building energy performance were t demanding. Beginning with 2002, in Romania has started the annual national programme for thermal revation of multi-family buildings built in period After 2009, this programme has had an acceleration process and the period was enlarged with more five years ( ). Initial, the intervention works contained new thermal insulation of exterior walls, replacement of the existing obsolete windows and hydrothermal insulation of the terrace. After new regulations, were added new intervention works, such as: new thermal insulation of the floor over the underground where the block was designed to include apartments on the ground floor, works for the dismantling of the installations and equipments mounted visibly on the façades/terrace of the residential block and their reassembling after the thermal insulation works have been completed. This national programme is financed by 80% from central and local budget and 20% from dwelling owners. Table 18 Overall assessment of technical/social feasibility for NZEBR in Romania NZEBR measure Proven techlogy (score 1-5) Possible technical risks in revation or with respect to the energy performance Impact on living space and other social aspects Overall assessment of technical feasibility (1=low risk, 5= high risk) Overall assessment of social feasibility (1=low risk, 5= high risk) External insulation of walls and roof (D ) Triple glass windows (D ) ESX ventilation with heat recovery (D ) 5 Thermal insulation must be designed correctly to avoid the thermal bridges. 2 This efficient measure is very important due to ensure the increase of the air tightness, but is mandatory to be implemented together with the ventilation system. 2 It could be difficult to design and install this new ventilation system due to the sizes of existing Insulation of the external wall and roof will determine the increase of indoor comfort. It contributes at increasing of indoor comfort. Installation of the ventilation system will need the moving of the residents for the

31 NeZeR Report on technical and social feasibility studies Page 31 of 58 NZEBR measure Proven techlogy (score 1-5) Possible technical risks in revation or with respect to the energy performance Impact on living space and other social aspects Overall assessment of technical feasibility (1=low risk, 5= high risk) Overall assessment of social feasibility (1=low risk, 5= high risk) DHW circulation losses II (D ) Individual measuring DHW (D ) LED lighting in common spaces and lighting control PV panels on roof (D ) Solar heat collectors on the roof (D ) buildings built without ventilation system (places for ventilation networks and control room). 4 No technical risks in revation 5 It could be difficult to install the individual heating meters due to the necessity to change the heat distribution from vertical system to horizontal system. 5 No technical risks in revation 5 The PV system has to be connected to the power grid for ensuring a rmal functioning and to avoid the building resistance issues through installing the supplementary electricity storage elements. 5 No technical risks in revation, only regarding the building resistance. duration of the works. It is necessary to be started a long and difficult awareness campaign for convincing the residents to approve this measure. After implementation the ventilation system, the indoor comfort will increase and the air quality will be improved. The decrease of water consumption will lead to decrease the utility bills of dwellings. The works for changing the internal heat distribution system could be unpleasant for residents. These works could influence the dwelling aspect, but the financial advantages could determine the residents to implement them. Residents become aware of their consumption, which could lead to decrease in energy consumption. This measure will contribute at decreasing the utility bills of dwellings. This measure will contribute at decreasing the utility bills of dwellings. This measure will contribute at decreasing the utility bills of dwellings

32 NeZeR Report on technical and social feasibility studies Page 32 of 58 5 SPAIN 5.1 National legislation framework The implementation of the Directive 2002/91/EC on the Energy Performance of Buildings (EPBD) and the corresponding recast (Directive 2010/31/EC) in Spain is the responsibility of the Ministry of Industry, Energy and Tourism, and of the Ministry of Public Works and Transport. The Institute for Energy Diversification and Saving (IDAE) also contributes to this process. Both Directives has been transposed to Spanish regulations by means of three Royal Decrees: Technical Building Code (Royal Decree 314/2006) - Energy saving Basic Document was published in This Basic Document comprises the following sections: - HE.1: Limiting energy demand (heating and air conditioning). - HE.2: Efficiency of heating/air-conditioning systems. - HE.3: Energy efficiency of lighting systems. - HE.4: Minimum solar contribution to the hot water supply. - HE.5: Minimum photovoltaic contribution to the electrical power supply. It was revised in 2013 by the Ministry of Development and it is applicable to new construction and major revations. Table 19 Building characteristics according to the TBC in Spain U values (W/m² K) Airtightness Roof Walls Floor Window Air permeability of windows and doors depend on the climatic zone. For zones A and B (Class 1, 2, 3 and 4), maximum air permeability is 50m 3 /hm 2. For zones C, D and E (class 2, 3 and 4), maximum air permeability is 27 m 3 /hm 2. Regulation of Thermal Installations in Building (Royal Decree 1027/2007) it was published in 2007 and updated in Energy certification of Buildings (Royal Decree 235/ The certificate is applicable for private residential, new construction and rehabilitation since The Spanish Government has developed and sent to the EU (July 2014) the "Longterm strategy for energy revation in the building sector in Spain, pursuant to Article 4 of Directive 2012/27/UE" in coordination with the National Action Plan for Energy Efficiency , sent to the EU on April 30, This strategy constitutes an important starting point for the promotion of energy rehabilitation of the building sector, as well as a roadmap that can guide to the different agents involved in an rehabilitation processes. It has been prepared by the Ministry of Development s Directorate General for Architecture, Housing and Land, in collaboration with the other ministerial departments involved, as well as taking into account contributions from the various working groups set up to develop it, other public administrations and the main actors in the sector. This Strategy includes the following elements:

33 NeZeR Report on technical and social feasibility studies Page 33 of 58 a) an overview of the national building stock based, as appropriate, on statistical sampling; b) identification of cost-effective approaches to revations relevant to the building type and climatic zone; c) policies and measures to stimulate cost-effective deep revations of buildings, including staged deep revations; d) a forward-looking perspective to guide investment decisions of individuals, the construction industry and financial institutions; e) an evidence-based estimate of expected energy savings and wider benefits. 5.2 Reference building The reference building is located in Sestao, in the rth of Spain. The climate is temperate and warm in Sestao. There is precipitation throughout the year in Sestao, even during dry months. According to Köppen and Geiger climate is classified as Cfb, Oceanic climate. The average annual temperature in Sestao is 14.2 C and precipitation is 1179 mm/year. Spain had a massive construction activity between the 50s and the 80s, time of boom due to industrial development period. They are all pre-rmative constructions. As a consequence, all the Spanish building stock erected during this period is of poor quality and highly inefficient in terms of energy performance. According to the results of the SECH SPAHOUSEC (SECH-SPAHOUSEC, 2011) project, the Spanish building stock is mainly composed of block of flats (70%) which are usually located in high density urban areas. According to SECH-SPAHOUSEC (2011), 60% of the buildings were erected between and 49% of the buildings erected before 1979 are multifamily blocks of houses. With regard to single family houses, a vast majority was erected in the last 30 years. The existence of standards in this period led to more strict building requirements with better determined constructive solutions and installations than multifamily buildings. Consequently, the most representative building typology in Spain will be characterized by the multifamily blocks constructed between The reference building selected for Spain is a multifamily building type with five floors, built in the The main technical characteristics and elements of energy building performance are presented in table 20. Table 20 Reference building data in Spain Specification Definition Unit Value Number of apartments apart. 20 Roof type Pitched roof without insulating material Total heated space area m Total heated living space volume m Total building volume m Heating source Electric radiators Heat source for DHW preparing Electric water heaters Electricity source Power grid Onsite RES Solar panels PV panels Biomass source Geothermal Source/heat pump

34 NeZeR Report on technical and social feasibility studies Page 34 of 58 Specification Definition Unit Value Ventilation Heat recovery Shading system (yes/) Blinds Heating period days 240 Lighting type Incandescent external walls W/m 2 K 0.81 Building elements (average U-value): windows W/m 2 K 5.7 roof W/m 2 K 1.56 floor slab W/m 2 K 1.30 Heating kwh/m 2 y Specific energy consumptions DHW kwh/m 2 y Electricity kwh/m 2 y 9.30 Heating MWh/y Annual energy consumption DHW MWh/y 45.3 Electricity MWh/y electricity MWh/y *conventional source MWh/y Energy supplied *RES MWh/y 0 -heat MWh/y 0 *conventional source MWh/y 0 *RES MWh/y Traditional building revation The traditional revation of the reference building includes measures for increase the building energy performance, such as: Building envelope: exterior walls: base and ventilated façade 130 mm mineral wool; roof: pitched roof and reflective insulation material 35 mm; windows: PVC frame with double clear glazing (air 6 mm); Lighting system fluorescent lamps (low electricity consumption) and natural lighting control; Heat source new individual natural gas boilers and water radiators and thermal solar panels Table 21 presents the new building energy performance after implementation of the traditional revation measures. Table 21 building data after traditional revation in Spain Specification Definition Unit Value Individual natural gas boilers and water radiators Individual natural gas boilers and solar panels Power grid Heating source DHW source Electricity source Onsite RES: Thermal solar panels PV panels Biomass source yes

35 NeZeR Report on technical and social feasibility studies Page 35 of 58 Specification Definition Unit Value Geothermal source/ Heat pump Ventilation Shading system blinds Heating period - days 240 Lighting type fluorescent + natural lighting control external walls W/m 2 K 0.21 windows frame W/m 2 K 2.2 Building elements (average U-value): windows - glass W/m 2 K 3.3 roof W/m 2 K 0.2 floor slab W/m 2 K 1.3 Heating kwh/m 2 y Specific energy demand DHW kwh/m 2 y Electricity kwh/m 2 y 9.28 Heating MWh/y 37.8 Annual energy consumption DHW MWh/y 46.2 Electricity MWh/y electricity MWh/y 12.7 *conventional source MWh/y 12.7 Energy supplied *RES MWh/y 0 -heat MWh/y 84.0 *conventional source MWh/y 70.6 *RES MWh/y 13.4 Figure 11 Building energy consumption: Reference building vs. Traditional revation (Spain) 5.4 More ambitious building revation - NZEBR This revation alternative of the reference building includes measures for increase the building energy performance, such as:

36 NeZeR Report on technical and social feasibility studies Page 36 of 58 - building envelope: exterior walls: base and ventilated façade 180 mm mineral wool; roof: pitched roof, reflective insulation material 35 mm and underfloor slab with 80 mm mineral wool; windows: wood frame with double low-e (argon 12 mm); lighting: LED and natural lighting control; heat sources: new biomass thermal plant and water radiators; electricity source: PV panels; ventilation: mechanical ventilation and heat recovery system Table 22 presents the new building energy performance after implementation of the more ambitious building revation measures Table 22 Building data after NZEBR in Spain Specification Definition Unit Value Heating source biomass thermal plant + water radiators DHW source biomass thermal plant Electricity source PV panels + Power grid Onsite RES: solar panels PV panels yes biomass source yes geothermal source heat pump Ventilation yes Heat recovery yes Shading system blinds Heating period - days 240 Lighting type LED + natural lighting control external walls W/m 2 K 0.15 windows frame W/m 2 K 1.58 Building elements (average U-value): windows - glass W/m 2 K 1.48 roof W/m 2 K 0.13 floor slab W/m 2 K 1.30 Heating kwh/m 2 y Specific energy demand DHW kwh/m 2 y Electricity kwh/m 2 y 9.28 Heating MWh/y 27.7 Annual energy consumption DHW MWh/y 48.2 Electricity MWh/y electricity MWh/y *conventional source MWh/y 12.7 Energy supplied *RES MWh/y heat MWh/y 75.9 *conventional source MWh/y 0 *RES MWh/y 75.9

37 NeZeR Report on technical and social feasibility studies Page 37 of 58 Figure 12 Building energy consumption: Reference building vs. NZEBR (Spain) 5.5 Ecomic data in analyzed alternatives Estimative investment costs The estimative investment costs of revation measures in both alternatives are shown in table 23 below: Table 23 Estimative investment costs and period for achieving the building revation in Spain Specification Unit Value (without VAT) Traditional revation Euro 236,260 NZEBR Euro 407, Annual costs The estimative values of annual costs corresponding to each building revation alternative and actual situation are presented in table 24. These costs include the all expenses for managing, operating, maintaining and repairing the building, such as: Energy costs (fuels, heat, electricity); Auxiliary costs (water, sewage, domestic waste, etc); Personnel costs (personnel working in connection with building operation, maintenance and management); Maintenance and repair costs Other annual operating costs. These values don t contain any amortization costs corresponding to the new investments for building revation.

38 NeZeR Report on technical and social feasibility studies Page 38 of 58 Table 24 Annual costs in Spain Specification Unit Value Reference building Euro/y 23,394 Traditional revation Euro/y 6,032 NZEBR Euro/y 6, Technical and social feasibility study of the NZEBR alternative In Spain, 77.7% of the buildings are privately owned while 14.5% are rented 8. As only the 14.5% of the buildings are for rent, there are specific energy rehabilitation activities undertaken in this type of ownership. Energy rehabilitation is mainly carried out by medium and large income owners. Private owners can receive loans for financing the revation activities from banks. Some support mechanisms are available when energy rehabilitation is undertaken. For low income owners, support is also provided when structural or accessibility problems are detected. Table 25 Overall assessment of technical & social feasibility for NZEBR in Spain NZEBR measure Proven techlogy (score 1-5) Possible technical risks in revation or with respect to the energy performance Impact on living space and other social aspects Overall assessment of technical feasibility (1=low risk, 5= high risk) Overall assessment of social feasibility (1=low risk, 5= high risk) External insulation of walls or roofs 5 Possible thermal bridges Change of aesthetical aspect 1 1 internal insulation of walls or roofs 5 Larger restrictions due to available space, thus, lower energy performance than external insulation Reduction of living area Change of aesthetical aspect May need to leave their house during installation 2 2 Double glazing 1 Special attention must be paid to air ventilation Air revation needed Thermal comfort 1 2 PV panels on roofs Solar thermal energy 4 Shading loss Shading loss Biomass 5 Strict management is needed to be sustainable Big storage place needed 3 4 ESX ventilation 3 Installation in a Access to apartments Ecomia.elpais.com published 30/01/2015

39 NeZeR Report on technical and social feasibility studies Page 39 of 58 existing building is costly Increase of the electric demand during installation Increase of the energy bill Regular maintenance must be provided

40 NeZeR Report on technical and social feasibility studies Page 40 of 58 6 SWEDEN 6.1 National legislation framework There are a range of international policies, such as Ecodesign Directive (Directive 2009/125/EC), Energy Performance in Buildings Directive (2010/31/EU) and Energy Efficiency Directive (2012/27/EU), which have an effect on the Member states national energy policies. Besides these policies, Sweden has different national energy policy instruments, administrative, ecomic, informational, and incentives that affect energy use and greenhouse gas emissions. Administrative The National Board of Housing s building Regulations (BBR) (BFS 2011: 26 - BBR19) is a fundamental policy tool for buildings energy use. BBR contains regulations and general recommendations for construction. Chapter 9 of the BBR concerns a building s energy conservation. The requirements placed on energy conservation in BBR are expressed in terms of the buildings maximum specific energy consumption per m 2 /year, and the dwellings heat transfer coefficient, U-value, which is a measure of the building's insulation capacity (BFS 2011: 26 - BBR 19) (Boverket, 2015) The Energy performance certificates scheme is an instrument with close links to the National Board of Housing. The law on energy certification of buildings (SFS 2006: 985) aims to promote energy efficiency and a good indoor environment (Energimyndigheten, 2010). According to the law, an energy performance certificate should be provided when a building (1) is sold, (2) rented, (3) being built or (4) is a large building occupied by public authorities and by institutions providing public services and therefore frequently visited by the public. This means that when any of the above occurs, an energy performance certificate should be made available to the prospective buyer, the prospective renter or building owner in each case. In order to simplify a comparison for the consumer, the energy declaration is reported with reference values. By establishing an energy performance certificate the government hopes to increase awareness of energy use in buildings, and thereby stimulate demand for buildings with lower energy demand (Naturvårdsverket, 2015). Environmental classification systems contribute to improvements in the building sector s environmental performance, such as energy efficiency improvements, reduced environmental impact and improved indoor environment, by assessing the building s environmental sustainability. The completed classification is third party audited; thereafter the building may receive a certificate. There are several national environmental classification systems, such as, Green Building, Miljöbyggnad and Svanen. In addition, LEED, which is a US-system and BREEAM, which is UKsystem, are also used in Sweden (Fjärrsyn, 2013). In addition, Passive house criteria have been developed in Sweden, as a result of Energy Performance in Buildings Directive, to ensure that dwellings meet the requirements of passive house.

41 NeZeR Report on technical and social feasibility studies Page 41 of 58 Ecomic Other key policies are energy and carbon taxes, these taxes provide financial incentives to implement energy efficiency measures, demand energy efficient solutions and phase out the use of fossil fuels. As of 2009 the government provides support to municipalities and county councils that perform energy efficiency measures in their own line of business. The municipalities and county councils that strategically perform energy efficiency measures receive financial support for five years. This governmental initiative is attributed 10.6 million EURO per year (Energimyndigheten, 2010). Informative The Swedish energy policy includes a range of different informative policies that promote the development of low-energy buildings. For instance, through government support there are municipal energy and climate advisory services which provide information and educate households, businesses, local organizations etc. Furthermore, the Swedish Energy Agency initiated the so-called LÅGAN-program (low energy consumption in buildings), with a budget of 2.3 million EURO over five years to promote NZEB/NZEBR on the occasion of new construction and revation. Ather policy of informative character is Energy labelling of products, the policy s issued by the Swedish Energy Agency, with the aim is to help consumers make sound energy decisions. For instance, the classification of windows is categorized from A-F of which category A has a U-value of 0.9. To receive the energy label the product must also meet stringent quality and performance requirements (Elitfönster, 2015). Other policies Techlogy procurement and market introduction have also proven to be effective instruments for development of new products and technical solutions for improving energy efficiency in residential and commercial premises. The Swedish Energy Agency has initiated a number of projects through networks (e.g. Belok and Bebo) and client groups, which sped up the market introduction and contributed to the development of low-energy buildings. Lastly, according to the Swedish government's reported plan of action, "The Road to near-zero energy buildings", (2011/12: 131), a Swedish application of the concept of near-zero energy building will be the legally binding level of energy requirements in Sweden. These requirements will be more stringent in relation to the demands of today s building regulations (BBR 19) as of Reference building Sweden is a Scandinavian country located in Northern Europe. Sweden borders to Norway in the west, to Finland in the rth east and to Denmark in the south west by a bridge-tunnel across the Öresund, which was built in Sweden is a constitutional monarchy and a parliamentary democracy, with the Monarch as the head of state. Sweden has an area of 447,419 square kilometers 9 (SCB, 2015a), which makes it the third largest country in the European Union 10. According to Statistics Sweden, the 9 The land area excluding inland water equals 407,339 square kilometres.

42 NeZeR Report on technical and social feasibility studies Page 42 of 58 total population is 9.76 million as per 28 th of February 2015, which gives a population density of 24 inhabitants per square kilometer (SCB, 2015b) The majority of the population lives in the Southern parts of Sweden, and about 85% of the population lives in urban areas (SCB, 2012). Stockholm is the capital city of Sweden and it is the country's cultural, media, ecomic, and political center. Stockholm is Sweden s, as well as the entire Nordic regions, most populous urban area (Stockholm Stad, 2015). Stockholm is also one of the five fastest growing regions in Europe. Since the 1980s the City has steadily increased its population, however in recent years there has been a vast increase. Between the end of 2008 and 2014 the population increased by over people and as of February 2015 there are inhabitants in the city of Stockholm. In 2020 it is estimated that Stockholm will have one million inhabitants (Stockholm Stad, 2015). Most of Stockholm s population, 90%, lives in apartments whereas the remaining 10% live in houses. Furthermore, in 2013, 44% of Stockholm s population were single-person households, 27% were two-person households and 29% were either three-person households or more. The city was founded during the early 1200s and it is located on Sweden's south central east coast where Lake Mälaren flows out into the Baltic Sea (Stockholm, 2015). The city is spread across 14 islands by the Stockholm archipelago and the geographical city center is situated on the water, in Riddarfjärden bay. Stockholm Municipality is a green city and just over 40 percent of the land is made up of parks and green spaces (Stockholm Stad, 2015a). There are many large recreation areas, parks, boardwalks and small neighborhood parks. Furthermore, the city has a temperate climate with four distinct seasons and the average annual temperature is 9 C with an annual rainfall of 61 mm (2014) (Stockholm Stad, 2015b). During the summer the average high daytime temperature lies between C and the lows lies around 13 C. Although located in Northern Europe, Stockholm has relatively mild weather compared to other locations at similar latitude, or even farther south. Stockholm have on average 2117 hours of sunshine every year, which is more than e.g. Paris, London and some other European cities of more southerly latitudes. The reference building represents a building type that is common in the greater part of Sweden and especially in the major cities. It is a multifamily residential building with four floors, constructed in the first part of the 1960 s. The building is located in the neighbourhood of Valla torg in the south part of Stockholm and the address is Sandfjärdsgatan The building structure consists of an aerated concrete masonry with a plaster façade. Floor slabs are cast in concrete. The roof slab is insulated with mm of mineral wool. All windows have wooden frames and double glazing from the construction year. However, the windows have been supplemented with external aluminium cladding in recent years. The balconies on the southern façade are also a late addition to the building. Entrance doors with sidelights and the garage doors on the rthern façade are all original. The building has a hydronic heating system connected to district heating. The air exchange is based on natural ventilation and the stack effect. 10 Only France and Spain are larger. Considering Europe, and t only EU, also Russia and Ukraine are larger than Sweden.

43 NeZeR Report on technical and social feasibility studies Page 43 of 58 Figure 13 Reference building in Sweden (Stockholm) Table 26 Reference building data in Sweden Specification Definition Unit Value Number of apartments apart. 51 Roof type low-sloping roof Total heated space area A temp is the Swedish definition of heated floor area used in m connection to EPBD. Total heated living space volume m Total building volume m Heating source District heating DHW source District heating Electricity source Power grid Onsite RES: solar panels PV panels biomass source geothermal source heat pump Ventilation yes Heat recovery Shading system Heating period - days 240 Lighting type Low-energy lighting, but t LED external walls W/m 2 K 0.54 Building elements (average U-value): windows W/m 2 K 2.7 roof W/m 2 K 0.24 floor slab W/m 2 K 0.54 Heating kwh/m 2 y Specific energy consumptions DHW kwh/m 2 y 29.4 Electricity kwh/m 2 y 8.0 Heating MWh/y Annual energy consumption DHW MWh/y Electricity MWh/y electricity MWh/y 36.4 *conventional source MWh/y 36.4 Energy supplied *RES MWh/y 0 -heat MWh/y *conventional source MWh/y *RES MWh/y 0

44 NeZeR Report on technical and social feasibility studies Page 44 of Traditional building revation The energy efficiency measures included in the traditional building revation are categorised and presented by the different technical systems in the building. Building envelope New weather-strips around windows and doors to improve the airtightness Original windows are revated and an additional window pane is added. The new U w -value is approximately 1.2 W/m² K. The roof is insulated with an additional 200 mm mineral wool. New U-value of about 0.13 W/m² K. Ventilation system Fans for exhaust air ventilation are installed to ensure adequate air exchange in the building. If the current air exchange rate is poor, this measure might in fact increase the energy use. Heating system The flows in the hydronic heating system are balanced and the heating control curve is adjusted accordingly. New efficient circulation pumps are installed. Domestic hot water system New water-saving taps are installed in bathrooms and kitchens. New efficient DHW circulation pumps are installed. Lighting and other electrical equipment New LED lighting in common spaces. Presence control of lighting in common spaces. Table 27 Building data after traditional revation in Sweden Specification Definition Unit Value Heating source District heating DHW source District heating Electricity source Power grid Onsite RES: solar panels PV panels biomass source geothermal source heat pump Ventilation yes Heat recovery Shading system Heating period - days 240 Lighting type LED external walls W/m 2 K 0.54 Building elements (average U-value): windows W/m 2 K 1.13 roof W/m 2 K 0.13 floor slab W/m 2 K 0.54 Heating kwh/m 2 y 79.1 Specific energy demand DHW kwh/m 2 y 24.9 Electricity kwh/m 2 y 9.2 Annual energy consumption Heating MWh/y 360.1

45 NeZeR Report on technical and social feasibility studies Page 45 of 58 Specification Definition Unit Value DHW MWh/y Electricity MWh/y electricity MWh/y 41.9 *conventional source MWh/y 41.9 Energy supplied *RES MWh/y 0 -heat MWh/y *conventional source MWh/y *RES MWh/y 0 Figure 14 Building energy consumption: Reference building vs. Traditional revation (Sweden) 6.4 More ambitious building revation - NZEBR The revation measures of the more ambitious revation of the Swedish building are presented below. Building envelope exterior walls: additional external façade insulation; U-value = 0.17 W/m² K roof: insulated with an additional layer by 400 mm mineral wool;u-value=0.08 W/m² K. windows are exchanged to new ones with triple glazing. The new U w -value is approximately 0.9 W/m² K. Doors in entrances and garages are replaced. U-values from 1.0 to 1.8 W/m²K. Ventilation system Fans for exhaust air ventilation are installed to ensure adequate air exchange in the building. Assuming that the current air exchange rate is poor, this measure will in fact increase the energy use. Heat in the exhaust air ventilation is recovered by installing exhaust air heat pumps, which will serve the heating system.

46 NeZeR Report on technical and social feasibility studies Page 46 of 58 Heating system The flows in the hydronic heating system are balanced and the heating control curve is adjusted accordingly. New efficient circulation pumps are installed. The piping in the basement is equipped with new insulation. The building energy management system (BEMS) is supplemented with a module for forecast control and algorithms for thermal storage in the building. DHW system New water-saving taps are installed in bathrooms and kitchens. New efficient DHW circulation pumps are installed. Metering devices for individual measuring and debiting of DHW are installed. Equipment for heat recovery from waste water (black water) is installed. Lighting and other electrical equipment New LED lighting in common spaces. Presence control of lighting in common spaces. Photovoltaic panels with a total area of approximately 200 m² are installed on the roof. A mir sensitivity analysis was made for the window and façade insulation measures. A combination of two types of windows and two sets of façade insulation was evaluated for total energy efficiency including all other measures. The result is shown in the table 28 below. Table 28 U-values and specific energy consumptions for some combinations of façade and window solutions in Sweden Combinations of façade/ window solutions Specific energy consumption Façade U-value (W/m² K) Window U-value (W/m² K) (kwh/m²y) Combination number 2 is the best option when only considering energy efficiency. However, to choose both a heavy insulation and a super-insulating window is t considered feasible from an ecomic point of view. For this scenario the second best combination, number 4, is chosen. Regarding the choice of a heat pump for heat recovery in the ventilation air, an exhaust and supply air ventilation system with heat recovery (ESX) was also considered. The ESX system requires new ducts for the supply air to each apartment and additional construction work in the attic and on the roof for the new air handling units. Due to these technical and ecomic reasons the heat pump solution is chosen.

47 NeZeR Report on technical and social feasibility studies Page 47 of 58 Table 29 Building data after NZEBR in Sweden Specification Definition Unit Value Heating source District heating DHW sources District heating Electricity source Power grid and PV panels Onsite RES: solar panels PV panels yes biomass source geothermal source heat pump Ventilation yes Heat recovery yes Shading system Heating period - days 240 Lighting type LED external walls W/m 2 K 0.17 Building elements (average U- windows W/m 2 K 0.90 value): roof W/m 2 K 0.08 floor slab W/m 2 K 0.54 Heating kwh/m 2 y 32.6 Specific energy demand DHW kwh/m 2 y 22.4 Electricity kwh/m 2 y 10.7 Heating MWh/y Annual energy consumption DHW MWh/y Electricity MWh/y electricity MWh/y 48.7 *conventional source MWh/y 18.7 Energy supplied *RES MWh/y 30 -heat MWh/y *conventional source MWh/y *RES MWh/y 0 Figure 15 Building energy consumption: Reference building vs. NZEBR (Sweden)

48 NeZeR Report on technical and social feasibility studies Page 48 of Ecomical data in analyzed alternatives Estimative investment costs The estimative investment costs of revation measures in both alternatives are shown in table 30 below: Table 30 Estimative investment costs for achieving the building revation in Sweden Specification Unit Value (without VAT) Traditional revation Euro 356,814 NZEBR Euro 882, Annual costs The estimative values of annual costs corresponding to each building revation alternative and actual situation are presented in table 31. These costs include the all expenses for managing, operating, maintaining and repairing the building, such as: Energy costs (fuels, heat, electricity); Auxiliary costs (water, sewage, domestic waste, etc); Personnel costs (personnel working in connection with building operation, maintenance and management); Maintenance and repair costs Other annual operating costs. These values don t contain any amortization costs corresponding to the new investments for building revation. Table 31 Annual costs in Sweden Specification Unit Value Traditional revation Euro/y 33,529 NZEBR Euro/y 26, Technical and social feasibility study of the NZEBR Alternative There are about 4,6 million dwellings in Sweden, approximately 2 million apartments are private houses and about 2.5 million are apartment buildings 11. Of these, 2.5 million apartments, the largest share, about 1.4 million are rental apartments, and about 900,000 are condominiums. Of these 1.4 million rental apartments, 50,4% are privately owned, 49,1% are municipality owned and the remaing are cooperative tenancy associations. About 40% of the houses of the reference type are municipality owned 12. There is special arrangement considering increases in rents for tenants. Regular maintenance is often included in the rent however, if the standard of living is increased (e.g. due to refurbishment of kitchen or bathroom) the rent will increase, as 11 Statistics Sweden och-bebyggelse/bostadsbyggande-och-ombyggnad/bostadsbestand/87469/87476/behallare-for- Press/374838/ 12 Sjögren.J.U Personal communication with Jan-Ulric Sjögren Stockholm Stad.

49 NeZeR Report on technical and social feasibility studies Page 49 of 58 the apartment's utility value has increased. In Sweden, energy efficiency revations are t considered to raise the standard of living and these do therefore t motivate an increase in rents. The tenants might however benefit from energy efficiency revations if the indoor environment (thermal comfort, acoustics etc.) of the apartment improves and by reduced energy costs. There is limit on the amount of rent increase after refurbishment. However, the rent increase should be fair, reasonable, and based on the apartment's utility value. This evaluated by comparing the rent of an apartment to the rent of a comparable apartment in the same area 13. If the tenant is under 29 years old and holds a low income he or she may be entitled to housing allowance. How much you can receive depends on your level of income, your housing costs and the size of your apartment. Table 32 Overall assessment of technical & social feasibility for NZEBR in Sweden NZEBR measure Proven techlogy (score 1-5) Possible technical risks in revation or with respect to the energy performance Impact on living space and other social aspects Overall assessment of technical feasibility (1=low risk, 5= high risk) Overall assessment of social feasibility (1=low risk, 5= high risk) External insulation of walls and roof 5 Exterior insulation of the wall and roof will cause changes on the architecture of the building. The thickness of the walls usually increases and this will cause some effects to the windows and would change the architecture of the building. In most cases the residents need to move out from the building for during the revation period. This means that temporary housing is needed, which could be difficult to find. Insulation of the external wall will cause better temperature condition in the departments. 1 2 Triple windows glass 5 It is of high important that one is thorough when conducting this type of measure in order to ensure air tightness. There will be positive effects for the residents in terms of better indoor environment and reduced drafts. 1 2 Exhaust air heat pump 4 Exhaust air heat pump significantly decreases the purchased heating energy and therefore the overall energy cost decreases. Installation of the exhaust air heat pump is relatively simple and it will t cause harm for residents. In addition, it leads to savings in energy costs Hyresgästföreningen, yra

50 NeZeR Report on technical and social feasibility studies Page 50 of 58 NZEBR measure Proven techlogy (score 1-5) Possible technical risks in revation or with respect to the energy performance Impact on living space and other social aspects Overall assessment of technical feasibility (1=low risk, 5= high risk) Overall assessment of social feasibility (1=low risk, 5= high risk) Adaptive heating control system DHW losses circulation Individual measuring DHW 4 This measure consists of different data and there is a risk that the data is t installed correctly, which will cause problems. 4 No technical risks in revation or with respect to the energy performance have been identified 4 The whole chain from measurement to debiting has to work and there is a technical risk that this chain does t work perfectly. ESX ventilation 4 In typical Swedish block houses new air conditioning channels have to be built and that may cause construction defects. Water saving tap 4 No technical risks in revation or with respect to the energy performance have been identified. Because the adaptive heating system is more adjustable to increased heat gains in an apartment, the residents will receive a more even indoor temperature. No impact on living space and other social aspects. Residents become aware of their consumption, which could lead to decrease in energy consumption. Revation of the ventilation is rmally a large revation project and therefore residents usually cant stay at home during the revation period. Thus, the revation has a negative effect on the residents. However, the revation of the ventilation system will improve the air quality in the departments. There might be a short adjustment period to the new water saving tap for the residents Thermal storage ground 5 If there is t eugh, circulation in the ground there is a risk that energy runs dry. PV panels on roof 4 Timing has a central role in the feasibility of a PV system. As most of solar No impact on living space and other social aspects. The new systems have effect on the living quality, but might cause

51 NeZeR Report on technical and social feasibility studies Page 51 of 58 NZEBR measure Proven techlogy (score 1-5) Possible technical risks in revation or with respect to the energy performance Impact on living space and other social aspects Overall assessment of technical feasibility (1=low risk, 5= high risk) Overall assessment of social feasibility (1=low risk, 5= high risk) electricity is generated (during daytime) when the demand is low. Therefore new techlogies such as efficient storage systems as well as political support in form of feed-in tariffs are important. savings in energy costs. PV panels may increase fire load. LED lighting in common spaces 5 No technical risks in revation or with respect to the energy performance have been identified. No impact on living space and other social aspects. 1 1

52 NeZeR Report on technical and social feasibility studies Page 52 of 58 7 ENERGY SAVINGS Taking as analysis base, the energy consumption of reference buildings from each studied country, the energy savings 14 are from 19% from 51% in first alternative, respective from 58% to 93% in comparison with the reference building situation. Figure 16 shows the energy savings in each country. Figure 16 Analysis of energy savings The increase of the conventional energy savings in NZEBR versus Traditional revation is medium 35% in studied countries, with a maximum by 42% for Spain and a minimum by 26% for Romania 14 only conventional energy

53 NeZeR Report on technical and social feasibility studies Page 53 of 58 8 SOCIETAL BENEFITS The building revation action provides several important societal benefits associated with reduced energy used, such as: - reduced dependence on finite conventional (fossil) fuels through deploying the RES; - increased energy security through rising the energy independence; - improved air quality through reducing the GHG emissions; - improved livability in the surrounding community; - increased employment through creating new jobs. The EU policies and strategies ackwledge the importance of building revation as a key element in reaching the long-term energy and climate goals, as well as having a positive ecomic impact. Table 33 presents the level of avoided GHG emissions in both revation alternatives: considering as the basis the level of GHG emission in the reference building case in each country using the GHG emission factors presented in table 28. Table 33 GHG emission factors Country Specification Unit Value -E-GHG emission factor (conventional sources) kg CO 2 e/kwh 0,33 Finland -H-GHG emission factor (conventional sources) kg CO 2 e/kwh 0,245 The Netherland Romania Spain Sweden -E-GHG emission factor (conventional sources) kg CO 2 e/kwh E-GHG emission factor (PV) kg CO 2 e/kwh H-GHG emission factor (conventional sources) kg CO 2 e/kwh E-GHG emission factor (conventional sources) kg CO 2 e/kwh H-GHG emission factor (conventional sources) kg CO 2 e/kwh E-GHG emission factor (conventional sources) kg CO 2 e/kwh H-GHG emission factor (conventional sources) kg CO 2 e/kwh E-GHG emission factor (conventional sources) kg CO 2 e/kwh E-GHG emission factor (RES-wind power) kg CO 2 e/kwh H-GHG emission factor (conventional sources) kg CO 2 e/kwh H-GHG emission factor (RES-biomass) kg CO 2 e/kwh 0.01 As it is shown in figure 17, the NZEBR alternative leads to a higher percent of the reduced of GHG emissions due to the decrease of energy consumption generated by conventional fuels and the development of RES

54 NeZeR Report on technical and social feasibility studies Page 54 of 58 Figure 17 Reduced GHG emissions Reference building vs. Traditional revation / NZEBR These results demonstrate the advantages of NZEBR over the traditional revation alternative in the partner countries and sustain the implementation of NZEBR measures by showing a significant increase of fossil energy savings and reduction of greenhouse gas emissions when comparing implementation of technical NZEBR measures in comparison with traditional building revation

55 NeZeR Report on technical and social feasibility studies Page 55 of 58 9 CONCLUSIONS Two revation alternatives of a selected reference building in each country were studied from the technical and social point of view. These two alternatives considered both the traditional building revation techlogy used in each country and implementation of NZEB concept for residential building revation. The analysis regarding the technical and social feasibility of NZEBR alternative led to the following aspects about influence of the specific measures in each country: Insulation of exterior opaque building elements it is already proven techlogy and the technical and social risks are minimums in all countries for exterior insulation system. It is assessed a small increase of risks (2 instead 1) in the case of implementation the internal insulation techlogy in Finland and Spain Efficient double/triple glass windows - the technical and social risks are minimums in all countries; it is already proven techlogy in Finland and Sweden, in rest of countries this techlogy is t usually used in revation works of residential buildings

56 NeZeR Report on technical and social feasibility studies Page 56 of 58 It remarks that only in Spain are used double glass window type taking into consideration the climatic conditions, in rest of countries are focused on triple glass windows as specific measure for NZEBR. Ventilation system it is already proven techlogy in Finland and Sweden, countries with large experiences to implement the ventilation system for residential buildings; in the rest of countries is difficult to be implemented for existing multi-family buildings. Taking into consideration the important size of this intervention work, the implementation of this measure could induce medium risks from technical and social point of view in all these countries.