REPORT | Sweden – Differences between Measured and Calculated Energy Use in EPCs versus Building Permits (New field study/2016)

EPCs in Sweden are based solely on the measured energy use in the building. The regulation requires that the measured energy use is corrected to normal use during a reference year, however, there is no standardised methodology to account for normal use in the EPC and this is therefore seldom done. This study is focused on investigating the cause of differences between the calculated and measured energy use in buildings, in order to detect compliance problems with measured EPCs. Analysis of two EPC databases for single-family houses and multi-family buildings is conducted based on interviews and complemented with energy use calculations, in order to identify and investigate potential general procedures and parameters that cause such differences. Suggestions on improvements to the Swedish EPC scheme are also presented.

Report | Spain – Different data/tools for getting EPC (New field study/2015)

The EPC for existing buildings in Spain can be obtained through several software tools, all of them equally valid for calculating the EPC. There is one reference tool, one detailed tool, and three simplified ones. All the simplified tools have passed a validation test procedure, in accordance with the guidelines given by the responsible authorities.

This study is an application of, and is focused on two of the three simplified tools, namely CE3 and CE3X, applicable to all types of buildings. A total of 38 buildings have been studied, starting from the information gathered at the point when they were each certified as an existing building, using one of the simplified tools. The sample of buildings includes all types of buildings: residential, small and medium tertiary buildings, as well as large tertiary buildings.

The study is carried out in two phases, with different aims:

PHASE 1: in which the results obtained through the tools using actual values are compared with those obtained using default values;

PHASE 2: in which the results of the simplified tools are compared with those obtained using the reference tool for the same building.

Reports | Romania – Assessment of Quality and Compliance in the Certification of Energy Performance of Buildings (New field study/2016)

Aim of this study was to give an overall qualitative analysis of the energy performance certification system in Romania, as well as to assess the quality and compliance of EPC (Energy Performance Certificate) input data based on EPCs received in the central collection point and introduced in the structured database. In this respect, 26 buildings which were certified during the year 2015 by attested building energy auditors (EAB) were examined.

Key objectives of the analysis were:

  • to analyse the overall quality and completeness of the EPCs introduced in the structured database with as aim to check general compliance with the requirements for the elaboration of EPCs;
  • to analyse the range of deviation of EPC energy performance indicators depending on the quality of input data (analysis of the EPC input data, site visits and re-calculation of EPCs);
  • to analyse the cause of the deviation and to develop recommendations on how to improve – deliver information to energy auditors for buildings;
  • to formulate recommendations for compliance and enforcement.

Reports | Greece – Compliance and Quality of Works in New Case Studies (New field study/2016)

This study assesses the quality of works, the compliance with the reference values of the National Technical Guides and the compliance with EPC input data for 26 newly built and renovated buildings in Greece.

The quality of works was studied based on on-site inspections and measurements, including airtightness tests, infrared thermography of the building envelope and site visits and inspections to check the actual construction.

The check of compliance with the reference values of the National Technical Guides included ventilation measurements and measurements of temperature and relative humidity.

Finally, the reliability of EPC input data was investigated by comparing the U-values of the design with the actual U-values of the materials used in the construction as reported in the EPC, comparing the design values of technical characteristics of the solar collectors with the technical characteristics used in the construction as reported in the EPC and checking the accuracy of EPC calculations.

 

 

Report | France – Compliance of regulatory and design studies on energy performance of new buildings (New field study/2016)

Since 2013, all new buildings in France are subject to an energy performance testing according to the regulatory calculation RT2012. The calculation uses various assumptions, concerning e.g. occupancy, temperature set point value and others, in order to position the building against the regulatory standards.

The objective of this study was to assess the results of the regulatory calculation, by comparing them with a Dynamic Thermal Simulation study. Twenty five (25) buildings were examined in this respect.

Report | Estonia – Summer Thermal Comfort Compliance in New Apartment Buildings (New field study/2015)

All buildings in Estonia, that have acquired a construction permit since 1 July 2009, have to comply with regulation no. 68 “Minimum requirements for energy performance”, that also regulates verification of summer thermal comfort compliance in buildings.

The objectives of this study were to assess the summer thermal comfort compliance of new apartment buildings, to characterise which building parameters cause overheating in dwellings and which properties will make a room ‘critical’ to be chosen for temperature simulation in the compliance assessment procedure.

Indoor temperatures were measured in 22 dwellings in 16 new apartment buildings during a three month summertime period and, for summer thermal comfort compliance assessment of the studied buildings, indoor temperatures in chosen dwellings most likely to counter overheating problems were simulated for in total 158 dwellings from 25 buildings.

Report | Cyprus – Compliance of heat transmission coefficients reported in EPCs in new residential properties (New field study/2015)

This study examines whether the minimum U-value requirements for the building envelope, as well as the average U-value of new residential properties in Cyprus are in accordance with the decrees issued by the MCIT, both as they were declared in the buildings’ Energy Performance Certificates (“EPCs”), and as they were built on site.

For this purpose, 27 new residential properties, located in the southern part of Cyprus, were investigated based on photographs, documents from suppliers, site visits, inspections, communications with architects, constructors, and, where possible, tenants.

In addition, a calculation of their U-values was conducted, taking into account the as-built situation, in order to check whether the buildings were built as designed, specified and declared in the EPCs, for as far as the examined construction elements are concerned.

Report | Belgium – Assessment of quality control framework for cavity wall insulation (New field study/2016)

Since 2012, a quality control system is in operation in Belgium to provide confidence in the quality of the works of cavity wall insulation in existing cavity walls. The system is managed by a quality control and certification organisation which is responsible for the assessment and approval of products and systems, the training of installers, and the conformity checks on building sites. When the works are in line with the quality control framework, the installer may provide a declaration of conformity to the client, which the client can use to receive subsidies or as an input for an energy performance certificate.

This field study was performed to analyse the relationship between the information provided by the installers in the declaration of conformity, the results of the conformity checks performed by the certification organization, and the effective cavity wall performance on site. The study is based on the field investigation of 26 detached and semi-detached houses, with retrofit cavity wall insulation installed in 2012 or 2013 under the quality control system. The analysis of the field study is focusing on both the compliance of input data and the quality of the works.

 

Report | Belgium – Compliance of EPC input data for window thermal performance in new buildings (New field study/2016)

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 the Belgian region of Flanders, and to derive recommendations to improve the compliance of the data. In addition, the study analyses the different compliant calculation methods for window thermal performance, in relation with the requirements in the Flemish regulation on Energy Performance and Indoor Climate in Buildings (EPB):

  • Maximum U-value windows
  • Maximum K-level (measure for the volumetric transmission heat loss)
  • Maximum net energy demand for heating
  • Maximum E-level (measure for total primary energy use of the project)
  • Overheating indicator (summer comfort)

To meet these objectives EPB-declarations, architectural drawings and glazing and framing product data were collected for 32 randomly selected projects.

Report | Austria – Assessment of EPC input data based on recalculation and on-site validation (New field study/2016)

In the federal province of Salzburg, the EPC is necessary in order to receive an energy-related subsidy, and the process follows a two-step procedure: to receive a construction permission, the planning EPC has to be issued and accepted by the officials; additional changes during the implementation planning have to be considered in the updated (or completion) EPC, which proves whether the final planning and completion of the building still meets the requirements in terms of energy performance in order to receive the subsidy. This two-step model can serve as role model procedure for other federal provinces in Austria.

This study investigates the Salzburg model concerning strengths, weaknesses, and lessons learnt. It is built around the following objectives:

  1. Comparison between planning and completion EPC of 26 multi-unit residential buildings in terms of quality and compliance of input data according to OIB Guideline 6 and adaptations on federal province level, evaluation and analysis of deviations.
  2. Recalculation of the completion EPCs of 26 multi-unit residential buildings by independent personnel according to OIB Guideline 6 and information specifically collected for this purpose such as implementation plans; evaluation and analysis of deviations.
  3. Detailed technical investigation of compliant input data concerning the impact of compliant default input values stated in OIB Guideline 6 compared to compliant specific input values according to detailed calculation procedures following OIB Guideline 6 including references to Austrian and ISO standards.
  4. On-site investigation of 11 selected buildings out of the 26 multi-unit residential buildings.