“status on the ground” overview of energy performance...

With contributions from: François Rémi Carrié (ICEE/INIVE, Belgium), Susanne Geissler (OEGNB, Austria), Arnold Janssens (UGent, Belgium), Pär Johansson (Chalmers, Sweden), Theoni Karlessi (NKUA, Greece), Marina Kyprianou Dracou (CYI, Cyprus), José L. Molina (USE, Spain), Horia Petran (URBAN-INCERC, Romania), Nikolaos Stathopoulos (ENTPE, France), Paula Wahlgren (Chalmers, Sweden)

www.qualicheck-platform.eu

Jarek Kurnitski, Kalle Kuusk, Raimo Simson

(Tallinn University of Technology, Estonia)

Overview of Energy Performance Certificate (EPC)

compliance, and quality issues on the groundSummary of all collected data

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“Status on the ground”

The sole responsibility for the content of this publication lies with the authors. It does not necessarily reflect the

opinion of the European Union. Neither the EASME nor the European Commission are responsible for any use that may

be made of the information contained therein.

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2 3 4

IMAGE CREDITS

1. Shutterstock / Dmitry Kalinovsky

2. Shutterstock / Ant Clausen

3. Shutterstock / pryzmat

4. Shutterstock / Nonwarit

QUALICHeCK 1

Contents

EXECUTIVE SUMMARY....................................................................................................... 3

I. INTRODUCTION ....................................................................................................... 5

II. EXISTING STUDIES .................................................................................................... 5

II.1 Transmission characteristics ................................................................................................................... 5 II.2 Airtightness ................................................................................................................................................ 6 II.3 Ventilation systems ................................................................................................................................... 6 II.4 Summer thermal comfort solutions ........................................................................................................ 7 II.5 Renewable systems (heat pumps, thermal solar, PV) ......................................................................... 8 II.6 Summary of the literature review .......................................................................................................... 9

III. COMPLIANCE FRAMEWORKS ........................................................................................... 9

IV. COMPLIANCE ASSESSMENT STUDIES IN FOCUS COUNTRIES ............................................................ 10

IV.1 Austria ...................................................................................................................................................... 10 IV.2 Belgium .................................................................................................................................................... 11 IV.3 Cyprus ...................................................................................................................................................... 13 IV.4 Estonia ..................................................................................................................................................... 14 IV.5 France ...................................................................................................................................................... 15 IV.6 Greece ...................................................................................................................................................... 15 IV.7 Romania ................................................................................................................................................... 16 IV.8 Spain ......................................................................................................................................................... 17 IV.9 Sweden ..................................................................................................................................................... 18

V. CONCLUSIONS ...................................................................................................... 19

2 Summary overview of EPC compliance and quality issues on the ground

QUALICHeCK 3

Executive summary

The main objective of the QUALICHeCK project is to respond to the concerns regarding the

reliability of Energy Performance Certificate (EPC) declarations and the quality of the works. To

understand the status on the ground, the QUALICHeCK consortium conducted a review of 31

previous studies dealing with measured performance, reliability of input data, quality of the works

and compliance frameworks. These studies covered all main technology areas:

transmission characteristics and airtightness

ventilation systems

summer thermal comfort solutions

renewable systems (heat pumps, thermal solar, PV)

Studies on transmission characteristics were very limited and mostly inconclusive, indicating that

real transmission performance of buildings is very seldom studied and would definitely need more

attention because of generally increased insulation thicknesses. Building air leakage related studies

showed both good and bad results and therefore a general conclusion on airtightness cannot be

drawn. The results indicate that poor ventilation can be seen as a major European problem area as

ventilation rates and noise typically did not comply with requirements in available studies. Available

data on summer thermal comfort compliance was very limited. Indicatively positive results were

found about heat pumps, solar thermal and other renewables, which showed good performance if

certified installers type schemes were applied.

New field studies conducted in the framework of the QUALICHeCK project resulted in quite many

non-compliance issues, for example:

In Austria, 20% of the EPC input data had not been updated between design and completion,

resulting in errors in Space Heating Demand assessments in the range of 5-28%.

In Estonia, 68% of the buildings investigated did not comply with the regulatory summer comfort

requirement.

In Greece, the percentages of non-compliance based on building design documentation for the

U-values of external insulation and for the solar collector’s area are 56% and 73% respectively.

In Romania, recalculation of the EPCs lead to a change in energy class in almost 40% of the sample

for the total energy use.

In Sweden, the non-compliance rate based on the availability of the EPC alone was found to be

56% on a sample of 100 new houses.

The non-compliance in the new field studies was evaluated on regulatory basis. The main aim of the

studies was to analyse whether the buildings and construction works meet the regulatory

requirements. The question whether the calculated performance meets the measured performance,

was not the main aim of the QUALICHeCK studies.

Despite these facts showing many non-compliance issues, the IEE QUALICHeCK project has revealed

that positive developments are ongoing in Member States to improve the situation. Systemic

changes evidently will need time, legislative changes are to be supported with relevant compliance

procedures, supervision, commissioning, performance measurements, monitoring, model solutions,

guidelines, training etc. in order to be successfully implemented into practice. Ambitious and

sophisticated systems (such as Austrian, Estonian and Swedish examples reported here) appear to be

more difficult to implement in practice and have longer learning curves; however, they all seemed

very promising as being capable to lead substantial performance improvements.

Regulatory compliance checks on samples had also positive effects. For example, in France every

new residential building, the actual envelope airtightness has to be justified, either by a

measurement, or by the application of an airtightness quality management approach. Experience

have showed that the building air leakage rate has steadily decreased since 2006.

One very important QUALICHeCK project finding is the lack of procedures and control mechanisms

to verify and quantify as-built energy performance. In the majority of studied focus countries,

compliance control is based on building permit documentation, i.e., on preliminary conceptual


design. Since many things typically change in design development as well as during construction it is

highly important to develop control mechanisms and procedures capable to verify and document

energy performance of the final design and later on handed over as-built energy performance.

Therefore, extending compliance frameworks in order to be able to assess and check energy

performance requirements after issuing the building permit appears to be a critical aspect to

consider to improve actual compliance to energy performance requirements.

Generally, field data collected and analysed in the framework of the QUALICHeCK project confirms

that problems exist with EPC quality and input data, the quality of the works, as well as with

compliance frameworks which all are in the development process because of movement towards

high energy performing buildings which realization in practice is evidently enormous work.

However, the progress can be seen, the status on the ground needs continuous monitoring and more

efforts should be put to systematic data collection in order to assure the credibility of energy

performance requirements and EPC system.

QUALICHeCK 5

I. Introduction

The EPBD directive 2002 and its 2010 recast have led to significant efforts in Member States to

improve the energy performance of buildings. The compliance of building energy performance

assessments and the quality of building works are increasingly important aspects needing continuous

attention and well developed procedures in order to be able to achieve stringent energy and indoor

climate targets in practice.

To understand the status on the ground, QUALICHeCK conducted a review of 31 previous studies

dealing with measured performance, reliability of input data, and quality of the works and

compliance frameworks. These studies covered all main technology areas:

transmission characteristics and air tightness

ventilation systems

summer thermal comfort solutions

renewable systems (heat pumps, thermal solar, PV)

Additionally, 10 field studies were conducted in 9 focus countries. Five of the new field studies

analysed EP compliance and EPC input data quality by site visits, check of design documentation

and new energy and EPC calculation to compare actual and reported energy performance. One

study was devoted for summer thermal comfort compliance, including temperature measurements

in Estonian apartments, check of design documentation and temperature simulations based on

actual solutions checked by site visits. Reliability of EPC issued with different calculation methods

was studied in Spain. The last three studies worked with transmission characteristics including a

quality framework for cavity wall insulation and input data on window thermal performance in

Belgium, and U-values compliance in Cyprus.

II. Existing studies

To understand the status on the ground, QUALICHeCK conducted a review of 31 previous studies

dealing with measured performance, reliability of input data, and quality of the works and

compliance frameworks.

A selection of representative examples from existing studies is given in this report. The total outcome

of the literature review can be found in the QUALICHeCK report Status on the ground.

II.1 Transmission characteristics

In the context of the Flemish VLIET-SENVIVV study between 1995 and 1998, 200 randomly selected

dwellings were analysed in terms of the average thermal insulation level (Figure 1, left):

50 dwellings with a building permit when there was no requirement (before September 1 1992)

50 dwellings with a building permit when the requirement was K65 (September 1992 – Augustus

1993)

100 dwellings with a building permit when the requirement was K55 (starting September 1993)

Figure 1: Average insulation level of dwellings (left) and average insulation levels of analysed dwellings

(right).

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Results showed that a very large number of the determined average thermal transmittances was

substantially above the requirements although all buildings had a declaration which indicated that

they met the requirements. Surprisingly, there was no difference in average insulation level for the

3 periods (Figure 1, right).

This study has highlighted that it had little sense to impose more severe requirements if nothing was

done at the level of compliance checks.

II.2 Airtightness

Since 2006, there has been a significant reward in the French energy regulations for good

airtightness, which has been combined with a minimum requirement for residential buildings in the

2012 version of the energy performance of buildings regulation. This means that for every new

residential building, the actual envelope airtightness has to be justified, either by a measurement,

or by the application of an airtightness quality management approach.

The French experience (QUALICHeCK-Factsheet-07) has shown that it seems to be generally

recognised that accounting for building airtightness in the energy performance regulation is

appropriate. This minimum requirement seems to have been well-integrated by front-runners and to

have allowed a reasonable transition to its generalisation to all new residential buildings. Bailly et

al. (2013) have shown that the building air leakage rate has decreased since 2006 and is now quite

stable around 0.5 m3.h-1.m-2 at 4 Pa (Figure 2), or about q50=2.8 m3.h-1.m-2 at 50 Pa (or n50=1.8 h-1).

Figure 2: Specific building air leakage rate at 4 Pa performance depending on the construction year of

buildings.

Source: Bailly, A., Jiang, Y., Guyot, G., Desfougères, F. 2013. Preliminary analysis of a French Buildings

Airtightness Database. 34th AIVC Conference, Energy conservation technologies for mitigation and adaptation

in the built environment: the role of ventilation strategies and smart materials, Athens, Greece, 25-26th

September 2013.

II.3 Ventilation systems

One of the aspects identified as inadequate or not properly functioning is ventilation. In this

technology area many studies reported poor performance which is illustrated by the following

examples.

A study conducted in Estonia concluded that ventilation airflow in apartment buildings built during

the period 1990-2010 often does not meet the indoor climate category II (EN 15251:2007)

requirements (Figure 3). Although the EN 15251 standard is not a regulation, it is often referred in

the building design documents as input source for ventilation design.

http://qualicheck-platform.eu/wp-content/uploads/2016/03/QUALICHeCK-Factsheet-07.pdf

QUALICHeCK 7

Figure 3: Ventilation airflow and ventilation air change rate of measured apartments.

Source: Uute_korterelamute_uuring_2012.pdf (in Estonian). EN 15251:2007. Indoor environmental input

parameters for design and assessment of energy performance of buildings-addressing indoor air quality,

thermal environment, lighting and acoustics.

In the French context, regulatory compliance checks on samples of the yearly production of new

buildings have been introduced since the early 1970s to urge contractors and project owners to

build according to the rules set by the building code and to monitor the application of the

regulations. A specific study on ventilation systems compliance in French residential buildings

(Jobert, 2012; Jobert and al., 2013) revealed that 604 dwellings out of 1,287 (47% of the sample),

do not comply with the ventilation regulation (Figure 4).

The main conclusion was that ventilation commissioning is an absolutely necessary step to ensure a

well working installation when handed-over, with positive match between in-use and planned

performance (QUALICHeCK-Factsheet-06).

Figure 4: Number of non-compliance or defects per category in a sample of 1287 dwellings.

Source: Jobert, R., Guyot, G. 2013. Detailed analysis of regulatory compliance controls of 1287 dwellings

ventilation systems. 34th AIVC Conference, Energy conservation technologies for mitigation and adaptation in

the built environment: the role of ventilation strategies and smart materials, Athens, Greece, 25-26th

September 2013. Jobert R. 2012. "La ventilation mécanique des bâtiments résidentiels neufs : État de l'art

général - Analyse qualitative et technique des dysfonctionnements". Mémoire professionnel, France, 125 p

II.4 Summer thermal comfort solutions

The Estonian housing stock technical condition study analysed the indoor climate in 28 apartment

buildings constructed between 1990 and 2010. Indoor temperature was measured in 61 apartments.

Results (Figure 5) showed that indoor temperature is higher than the requirement in 65% of the

measured apartments.

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Figure 5: Indoor temperature in measured apartments, new buildings (left) and old buildings (right).

II.5 Renewable systems (heat pumps, thermal solar, PV)

A more positive situation was found with renewable energy systems. The French study of quality of

solar thermal domestic hot water systems in houses showed that 93% of the audited installations

had an excellent (70%) or good quality (23%). The quality was insufficient for 6% of the audited

installations (Figure 6). Good results were achieved due to the approach in which French installation

companies of solar thermal systems can apply for the qualification QualiSol, in order to show to

customers their skills for installing such systems. The quality label Qualisol is managed by the

French association Qualit'EnR. Each certified company is submitted to an audit by Qualit'EnR, at

least once every three years.

Figure 6: Results of the audits by Qualit'EnR on solar thermal domestic hot water systems under the quality

label Qualisol. (dark green: excellent, light green: good, orange: insufficient, red: failing).

Analysis of performance of residential heat pump systems in Germany showed that carefully planned

and correctly installed heat pump systems reach efficiencies which enable ecological and economic

advantages compared to fossil heating systems. Within the evaluation period (July 2007 to June

2010) ground source heat pumps reached an average seasonal performance factor (SPF) of 3.9 and

air source heat pumps a SPF of 2.9. The SPF of three evaluated water source heat pumps was

determined at 3.7 (Figure 7).

QUALICHeCK 9

Figure 7: SPFs of ground source heat pumps.

II.6 Summary of the literature review

The main findings from the literature review may be summarised as follows:

There is limited data on transmission characteristics (additional studies needed).

Building leakage showed both good and bad examples.

Poor ventilation could be seen as a major European problem: ventilation rates and noise often

did not comply.

There is limited data on summer thermal comfort (not well addressed in building codes).

Heat pumps, solar thermal and other renewables showed good performance if certified installers

etc. schemes were applied.

III. Compliance frameworks

Often, compliance frameworks stopped to schematic design/building permit whereas the final

design, construction phase and as-built energy performance was not controlled after the building

permit was issued. Only 4 out of 9 countries had compliance frameworks extended to final design

and construction and commissioning phases, Table 1 (QUALICHeCK-Booklet-1).

Table 1: Overview of time frames for energy assessment requirements for new buildings.

Assessment typea Calculated (asset) Measured

(operational)

Sub-typea Design As-built Actual

Typical time frame Building permit After completion of

the works

<2 years after

completion

Used for EPC Yes No Yes Yes

Country

Austria b

Belgium

Cyprus

Estonia

Spain

France c

Greece

Romania c

Sweden c a Defined in FDIS ISO 52000-1:2016 (Energy performance of buildings — Overarching EPB assessment) b Depends on the region c Not based on EPC method

http://qualicheck-platform.eu/wp-content/uploads/2016/05/QUALICHeCK-Booklet-1.pdf


This means that the remaining 5 countries did not have a clearly defined control mechanism and

related practices how to take into account changes in final design and production information as

well as design changes during construction. No common practice was found from commissioning

procedures, which were typically not EPBD driven, but more related to good practice, Table 2

(QUALICHeCK-Report-Overview-of-existing-studies).

Table 2: Typical examples of approval procedures in design and construction phases

Preliminary design to

apply building permit

Building permit is issued by local authority based on (preliminary) scheme

design documentation and EPC.

Final design/production

information

Usually there is no official control mechanism for final design stage, energy

calculations are not required to be repeated (exemption e.g. province Salzburg

where a design EPC and a completion EPC is required).

Design changes

The building owner, or the site supervisor representing the building owner, is

responsible to fulfil legal obligations such as the energy performance minimum

requirements and in the case of significant design or component changes,

energy calculations have to be revised, but as there is no control mechanism,

this is not followed in practice.

Commissioning

Commissioning includes several measurements, but is only required for the

housing subsidy scheme and for voluntary building certification (e.g. TQB,

klima:aktiv, Passivhaus)

Completion

announcement, handover

and permit of use

The building authority issues the permit of use based on the completion

announcement and connected with a site visit, but in fact there is no

inspection. With the permit of use the building may be occupied.

Operation phase New energy certificate after 10 years is mandatory.

IV. Compliance assessment studies in focus countries

The main objective of the QUALICHeCK project is to respond to the concerns regarding the

reliability of Energy Performance Certificate (EPC) declarations and the quality of the works. In

order to analyse the situation in the ground, compliance assessment studies were conducted in 9

focus countries. Five of the new field studies (Austria, France, Greece, Romania, Sweden) analysed

energy performance compliance and EPC input data quality by site visits, check of design

documentation and new energy and EPC calculation to compare actual and reported energy

performance. Three studies (two in Belgium, one in Cyprus) worked with transmission

characteristics including quality framework for cavity wall insulation and input data on window

thermal performance and U-values compliance. One study (Estonia) was devoted for summer

thermal comfort, including temperature measurements, check of design documentation and

temperature simulations based on actual solutions checked by site visits. Reliability of EPC issued

with different calculation methods was studied in Spain.

IV.1 Austria

Assessment of EPC input data based on recalculation and on-site validation

QUALICHeCK-Factsheet-12

The Austrian study analysed the compliance of 26 multi-family buildings in the Salzburg region

constructed between 2009 and 2014 that applied for energy-efficiency subsidies. To be eligible for

such subsidies in this region, in addition to filing an EPC for the building permit application showing

compliance to the specific subsidy programme requirement, applicants also have to file an updated

compliant EPC upon completion of the building. The study recalculated EPCs based on original

building documents such as site foreman's plan and, by comparing original EPCs and recalculated

EPCs, investigated reasons for errors in determining input data.

http://qualicheck-platform.eu/wp-content/uploads/2015/06/QUALICHeCK-Report-Overview-of-existing-studies.pdf


QUALICHeCK 11

Figure 8: Space Heating Demand (SHD) values (site specific climate) of the original planning, completion, and

re-calculated EPC of 26 subsidised multi-family buildings received from Salzburg Wohnbau GmbH.

The study showed that, although required, the EPC input data had not been updated in 5 buildings

out of 26 (20%) resulting in errors on Space Heating Demand assessments in the range of 5-28%

(Figure 8, buildings 6, 13, 15, 16, 21). The deviation between the planning and the original

completion EPCs is less than 5% for 17 out of the remaining 21 buildings, mainly due to design

changes. Reasons for large deviations are changes in regulation and software updates between

issuing the planning EPC and the completion EPC. The recalculated EPCs deviate from the original

completion EPCs between 29% and 38%. The root mean square of the relative error is 16%. Main

reasons are different interpretation of rules and compliant multiple data input options (default

values, calculated values, simulation results).

The study confirms that clear rules for determining input data, which at the same time allow for

easy checking of compliance, need more attention. There is a strong indication that the existing

range of interpretation concerning input data for EPC calculation poses a barrier to quality control,

comparability of EPCs, evaluation and policy assessment, and further development. More precise

definitions in relevant documents on the federal level and on the provincial level are needed and

contradictions have to be avoided.

IV.2 Belgium

Compliant EPC input data for window thermal performance


The objective of this study is to provide a better understanding of the compliance of input data

related to window thermal performance in EPB declarations for new buildings in Flanders, and to

derive recommendations to improve the compliance of the data. EPB-files, EPB-declarations,

architectural drawings and window component product data (glazing and framing) were collected

for 32 randomly selected projects assessed by 15 different EPB-assessors: 1 office building, 22

single-family houses and 9 apartments (311 windows in total). For each of the 32 projects, the EPB-

files were screened and the U-value of all the windows was recalculated. The recalculated values

were compared to the input data in the EPB-declarations.



Figure 9: Comparison between the mean window U-value in the 32 original EPCs and the mean window U-value in the recalculated EPCs.

Figure 9 shows the comparison between the mean window U-value in the 32 original EPCs and the

mean window U-value in the recalculated EPCs (area weighted average) using the same calculation

method as in the original EPC. In 4 of the 32 EPB-declarations (12.5%), the window input data were

not correctly reported compared to the information given in architectural drawings and

manufacturer data. Wrong values of window areas were used in 3 of these 4 cases, while in one case

wrong U-values of the window frame were used, leading to a maximum deviation of 24% of the

mean window U-value. The method of calculation did not have an influence on the prevalence of

reporting errors.

In 2 out of 32 projects (6%), one or more of the EPB-requirements were not met, but only in one

case this was related to wrong window input data. When the correct frame U-values were used

instead of the erroneous values entered by the EPB-assessor, the K-level of the project exceeded

the requirement by 2.5%. In the other case, non-compliance was related to the value of the

overheating indicator, which was 15% higher than the maximum limiting value, but this was not

caused by non-compliant input data.

Quality control framework for installation of thermal insulation in cavity walls


The second Belgian study dealt with a quality framework for cavity wall insulation of existing

buildings aiming at securing the insulation level attained by companies providing this service. The

26 detached and semi-detached houses selected for this study were built between 1928 and 1995.

The study showed that the cavity width of the insulated cavity wall was often not reported correctly

by installers and was therefore often not compliant with specifications. In 12 out of 26 cases (46%)

the cavity width was reported as a single value, while multiple measurements should have been

taken and reported. However, based on the comparison between measured and calculated U-values,

there was no evidence that the reported values were wrong. In none of the cases the measured U-

value was significantly higher than the theoretical value (Figure 10). There were in general little

deviations between the wall areas provided by the installers and the re-calculated ones during their

investigations, deviations as high as 17% and 39% were observed on 2 specific cases, respectively. In

62% of the cases, the deviation is smaller than 2.5%—an acceptable deviation defined within this

study. Note, however, that there is no acceptable deviation range for the reported wall area

defined within the framework itself, making it difficult to state whether the wall area is compliant

or not.


QUALICHeCK 13

Figure 10: Comparison between measured and calculated U-values in the case-studies (dashed lines represent

the confidence interval taking into account 10% measuring uncertainty).

Although in none of the case studies the installation of insulation was part of a major renovation for

which energy performance requirements applied, the U-values achieved in the case studies were

compared to the requirement that would be in force in that case. The comparison showed that it is

difficult to meet the requirement in cavity walls with a cavity width smaller than 60 mm. It is

recommended to investigate the development of insulation products with improved thermal

properties compared to the approved existing products in order to meet energy performance

requirements in existing cavity walls with narrow cavities.

IV.3 Cyprus

Differences between calculated U-values in EPCs versus actual U-values


The Cyprus study analysed the EPC versus as-built U-values of 27 new residential buildings with

representative construction methods located in the Southern part of Cyprus. Calculation of building

envelope U-values was conducted taking account of the as-built situation in order to check whether

the buildings were built as designed, specified and declared regarding those specific elements.

Results showed that 10 out of the 27 buildings examined (37%) did not comply with the applicable

decree and identified 6 major reasons for the discrepancies between the EPC and as-built data, as

summarised in Figure 11.

Figure 11: Reasons for deviations between actual U-values and those reported in the EPCs.



IV.4 Estonia

Summertime overheating prevention requirements and compliance

assessment


The Estonian study was focused on summer thermal comfort. In Estonia EPBD Annex I requirement:

“1. The energy performance of a building shall be determined … and shall reflect the … cooling

energy needs (energy needed to avoid overheating) to maintain the envisaged temperature

conditions ...” is addressed by a requirement not allowing to exceed +27°C more than 150 Kh

(Kelvin hour) in residential buildings and +25°C more than 100 Kh in non-residential buildings from 1

June till 31 August, to be simulated with standard building use and test reference year. The

principle of the temperature simulation based requirement is shown in Figure 12.

Figure 12: Estonia limits temperature excess over 27 °C to 150 Kh in residential buildings, to be proved by

dynamic temperature simulation in critical rooms.

The study showed that evidence of compliance was available in only 8 out of the 23 buildings (35%)

simulated, and that in 4 cases (17%), the information was incorrect. It also showed that 17 out of

the 25 buildings investigated in total (68%) did not comply with the regulatory requirement (Figure

13).

Figure 13: Assessment of overheating index in 25 buildings (based on simulated hourly mean room temperature in degree-hours above 27°C in "worse case" dwellings between 1 July and 31 August).

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QUALICHeCK 15

IV.5 France

Compliance of regulatory and design studies of energy performance of new

buildings


The French study consisted of a comparison between a regulatory and a forecast calculation of the

energy use of 25 newly built dwellings. The selection of the buildings was mostly driven by the fact

that detailed descriptions, as well as regulatory calculations, were provided by an engineering

design office. A Dynamic Thermal Simulation of 25 buildings was performed using EnergyPlus-Design

Builder software, investigating energy performance for Heating, Cooling, Domestic hot water,

Lighting, Auxiliary heating and ventilation. Results are then compared with the ones acquired by the

regulatory calculation tool PERRENOUD, used by the engineering design office.

Figure 3: Comparison between regulatory and dynamic simulation total energy consumption results, 25 buildings.

The results show small differences between regulatory calculations (performed by the engineering

design office) and simulation results (performed with EnergyPlus - Design Builder by the ENTPE) for

most of the compared values. For example, the minimum relative error between the two compared

results for the total energy consumption is 0.76% (building 6) and the maximum one is 9.97%

(building 17). Figure 14 confronts results obtained with the two different calculation tools

concerning total energy consumption.

IV.6 Greece

Comparison of the implemented U-values as reported in the EPC with the

design U-values


In the Greek study, the compliance with EPC input data regarding U-values was investigated for

twenty-three (23) building case studies with the following procedures by comparing the U-values of

the design with actual U-values of the materials used in the construction as reported in the final EPC

and checking the accuracy of EPC calculations. The input values of the buildings’ automation and

control systems, as well as the values of the buildings’ heat capacity and U-values of door and window

frames and external insulation were checked in the EPC calculation file. When a value in the EPC

calculation file was not in accordance with the actual value, it was corrected and the software was

executed again in order to determine the actual energy class of the building.

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Figure 4: Design vs implemented U-values for external insulation

Concerning the external insulation, in three buildings (19%) the U-values were found to be identical,

in four buildings (25%) the construction U-values are higher than the design U-values, whilst there

were also four buildings (25%) with U-values lower than the design values. Hence it is concluded

that 44% of the case studies show compliance and 56% of them are not compliant. Figure 15

provides a graphic representation of design vs implemented U-values for external insulation.

With respect to the door and window frames, it was found that in seven buildings the U-values were

identical (32%), in six buildings (27%) the U-values of those installed were lower than the design

values and only one (5%) building implemented higher U-values than the design ones, as shown in

Figure 1. Thus 59% (32+27) of the case studies show compliance and 41% (5+36) of them are not

compliant.

IV.7 Romania

Quality and compliance in the certification of energy performance of

buildings


The study focused on the assessment of the overall quality and completeness of EPC based on the

structured database containing 37,700 EPC (2015) and the key data (identification, energy

performance) were studied in order to identify frequent errors and to produce recommendations for

future activity of energy auditors for buildings. The study also consisted the investigation of EPC

elaborated in 2015 for 26 residential buildings, covering a selection of a variety cases (size, EPC

purpose, issuer, building age, climatic zone, rural and urban areas, etc.).

Deviations in the assumptions and calculation of input data were found in 8 buildings, with errors up

to 63% on the net floor area and up to 40.4% on the heated volume of the building. More than two

thirds of analysed EPCs showed differences ranging from 0.2% to 46.2% on the heat transfer area of

building envelope. Both types of errors in geometry characterisation might lead to important

deviations in the final energy performance indicator. U-values deviations were observed for 85% of

analysed EPCs and varied between -0.108 W/m²K to 0.781 W/m²K compared to the corrected

average U-values of the building envelope. These deviations can be explained by incorrect

assumptions regarding insulating material thickness or thermal conductivity and by the incorrect

calculation of thermal bridges.

The deviations on the energy performance indicators noticed in the recalculation of analysed EPCs

lead to a change of energy class in almost 40% of the sample for the total energy use and 50% for

space heating. The deviations are generated not only by differences in input data, but also by the

differences in the various software tools used, due to the lack of validation system for these tools.


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For the total energy use deviations larger than ± 5% were noticed in 18 out of 26 cases, while

deviations larger than ± 10% were observed in 15 out of 26 analysed EPC (Figure 16).

Figure 16: Values for the total energy use and deviation noticed in EPC

Taking into account the target of 10% of issued EPC which have to be checked for compliance each

year, adequate procedural tools and appointment of relevant independent experts for the actual

checks of EPC further need to be detailed for an effective implementation of these provisions.

IV.8 Spain

Different data and tools for calculating EPC


The Spanish study compared energy class results of 40 EPCs of existing buildings obtained with three

official, equally valid, asset rating methods. Two of the rating methods are simplified and are

meant to be used in existing buildings (residential and non-residential); the third one is a detailed

method, which is applicable to all new and existing buildings.

Figure 17 shows large deviations in the energy classes obtained with the different methods. In one

case, the detailed method rates the building as energy class A while one simplified method gives

energy class G (i.e., deviation of 6 energy classes). Except for one case, the simplified tools always

give a worse energy rating than the detailed one. Over-simplification of geometrical characteristics

of the buildings by the EPC experts was identified as a major source of errors.

Figure 17: Comparison of classes of energy obtained with simplified and detailed EPC calculation methods. The area of the bubbles is proportional to the number of cases: the smaller is one case and the greater is 5.



IV.9 Sweden

Differences between measured and calculated energy use in EPCs versus

building permits


The Swedish energy performance of buildings context for new buildings is very specific compared to

other European countries because the EPCs of new buildings are required within 2 years of building

completion based on measured values, not a value calculated from building characteristics. An asset

rating is required for the building permit.

Aim of Swedish study was to investigate the cause of differences between the calculated and

measured energy use in buildings. The study was based on interviews, analysis of two databases

with EPCs in single-family houses and multi-family buildings, complemented with energy use

calculations to identify potential general procedures and parameters that cause these differences.

The study showed that, out of a sample of 100 new houses applying for building permit in Lerum

municipality, 44 actually had a valid EPC after 2 years of operation. In other words, the non-

compliance rate based on the availability of the EPC is of 56%. The main problem causing this non-

compliance, in the view of the municipality of Lerum, is that the municipality cannot legally

demand an EPC from the owner and the owner is often reluctant to pay the fee (300 - 500 €) for the

EPC.

In addition, they found large discrepancies between measured and calculated energy use (Figure

18), without being able to conclude on their implications in terms of compliance. There are 29

houses of the 44 which have a difference between the calculation and measurement larger than

10%. Smaller than 10% is considered acceptable. The average difference is 25%, while the house

with the largest difference has a 113% larger measured energy use than calculated. Since the

calculations are performed at an early stage and may not have been updated with the latest

drawings and information, these results are only indicative.

Figure 18: Calculated and measured energy use for 44 single family houses in Lerum municipality, Sweden.

The blue line indicates a perfect match between the calculated and measured energy use. The area above and below the red lines indicates a deviation greater than 10% from a perfect match.

Poor agreement between the calculated energy use for the building permit and the energy use

reported in the EPC can also be caused by energy that is not used in the building (e.g. heat losses in

culverts). Furthermore, the measured energy cannot always be assigned to a specific building in a

block of buildings, or the measured energy use is not allocated to the right type of use according to

the definitions (e.g. washing machines in common laundry).

The measured energy use in buildings should be corrected to normal use during a reference year.

The correction for abnormal use is seldom done since there is no follow-up on deviations in

occupants’ behaviour and there is no official definition on normal use. The calculation study

revealed that the energy use in a single-family house can vary with more than 30% due to

occupants’ behaviour. The most important parameter is the variation in hot water use. This is

seldom measured separately.


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V. Conclusions

QUALICHeCK analysed the energy performance related quality and compliance situation in 9 focus

countries: Austria, Belgium, Cyprus, Estonia, France, Greece, Romania, Spain and Sweden. To

understand the status on the ground, QUALICHeCK conducted a review of 31 previous studies

dealing with measured performance, reliability of input data, quality of the works and compliance

frameworks. Additionally 10 field studies were conducted in the focus countries.

Most of the studies raise questions related to compliance frameworks. Often, compliance

frameworks stop to schematic design/building permit, whereas the final design, construction phase

and as-built energy performance was not controlled after the building permit was issued.

Based on the review of 31 existing studies it can be concluded that:

Poor ventilation is seen as a major European problem, as ventilation rates and noise typically did

not comply with requirements.

Ductwork airtightness is an issue in Central Europe, but was solved 30 years ago in Northern

Europe.

Building leakage showed both good and bad examples.

Studies on transmission characteristics were quite limited and mostly inconclusive.

Heat pumps, solar thermal and other renewables showed good performance if certified installers

type schemes were applied.

Available data on summer thermal comfort was very limited, however the issue was somehow

addressed in the majority of building codes.

New field studies conducted by QUALICHeCK show:

In many countries, a development with a 5 year step can be seen – new requirements and

procedures in 2007, 2012, etc. have been launched.

Systemic changes evidently will need time, legislative changes are to be supported with relevant

compliance procedures, supervision, commissioning, performance measurements, piloting,

model solutions, guidelines, training etc.

More ambitious and sophisticated systems (as shown by the Austrian, Estonian and Swedish

examples reported here) are more difficult to implement in practice – longer learning curves.

Compliance frameworks are to be extended in many countries in order to be able to assess as

built performance – in about half of the studied countries, control mechanisms stopped to

building permit phase.

Generally, field data collected and analysed in the framework of the QUALICHeCK project confirms

that problems exist with EPC quality and input data, the quality of the works, as well as with

compliance frameworks which all are in the development process because of movement towards

high energy performing buildings, the realisation of which in practice is evidently enormous work.

However, progress can be seen, the status on the ground needs continuous monitoring and more

efforts should be put to systematic data collection in order to assure the credibility of energy

performance requirements and EPC system.

Project Partners

“status on the ground” overview of energy performance...

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