The renewing of Energy Performance Certificates—Reaching comparability between decade-apart energy records

Abstract

Energy Performance Certificates are currently one of the most extensive data sources about the energy performance of the EUs building stock and consequently provide support for researchers and policy makers in energy regulation. As Energy Performance Certificates are being renewed, there are new possibilities to study energy performance development over time and to evaluate the building-specific effect of energy policies and measures. This paper aims to explore this possibility. In Sweden, owners of multifamily buildings had to obtain their first Energy Performance Certificate no later than the end of 2008, and with a period of validity of 10 years many owners have now obtained a second Energy Performance Certificate for their building(s). This enables unprecedented quantitative, building-specific evaluations of the change in energy performance over time. However, comparability between old and new Energy Performance Certificates must be assured. This study develops a novel three-step method to attain comparability between old and renewed Energy Performance Certificates. Results show that while many pairs of Energy Performance Certificates were considered comparable, procedural changes in methods for determining heated floor area in Swedish Energy Performance Certificates caused an overestimation of energy performance improvement of approximately 7 kWh/m2 per building which had to be corrected for. The results of this paper indicate that old and renewed Energy Performance Certificates can be utilised to successfully map development of energy performance and enable evaluation of the impact on energy performance from policies and measures that have been carried out between the two points of audit.