Energy consumption of high-performance buildings: Design vs. Reality

Stefano Cozza,Martin K Patel,Carlo Gambato,Giovanni Branca,Achim Geissler,Jonathan Chambers

doi:10.1088/1742-6596/1343/1/012169

Abstract

Studying the performance of highly efficient buildings is crucial for future policy, for example to inform decision making about whether to pursue further thermal improvement of buildings (insulation) or to rather foster investments in renewable resources. For this purpose, reliable values of the energy demand of new and retrofitted buildings are needed. However, there is evidence of a significant Energy Performance Gap (EPG) in buildings, defined as the difference between measured and calculated energy consumption. The objective of this paper is therefore to quantify the EPG in high efficiency buildings in Switzerland. The EPG was studied for 56 residential buildings, including various construction standards (Minergie, Minergie-P, and Minergie-A) and building types (new and retrofitted). The Minergie indexes were used as theoretical consumption, thereby representing the total final energy consumption for all needs of the buildings. These values were compared to data based on measurements. For the buildings in the sample the analysis yields a negative EPG of -14% (i.e. the median building consumes slightly less than its standard), indicating that the most efficient buildings are more robust to the EPG. However, this finding could be partly a consequence of the small sample used and its characteristics.

Highlights

Buildings are responsible for 40% of the total final energy consumption in the European Union as well as in Switzerland [1,2]
The Energy Performance Gap (EPG) was studied for 56 residential buildings, including various construction standards (Minergie, Minergie-P, and Minergie-A) and building types
The Minergie indexes were used as theoretical consumption, thereby representing the total final energy consumption for all needs of the buildings

Summary

Introduction

Buildings are responsible for 40% of the total final energy consumption in the European Union as well as in Switzerland [1,2]. The theoretical consumption used to calculate the EPG is approximated using the target of each Minergie standard [6], and does not change for each building, but is a fixed value below which all buildings should be This approach is chosen because the theoretical consumption data for each building is not available in the Solar Agentur database. The scope of the analysis only considers residential buildings, reducing the sample size to 115 buildings Some of these buildings are equipped with biomass or gas boilers, but it is impossible to know the share coming from the different energy carriers to apply the proper weighting factor (i.e. the amount of gas used for the heat supply and the amount of electricity used for lighting and appliances). This last filtering step reduces the final sample to 56 buildings

Results

Findings

Conclusions