Performance gaps in Swiss buildings: an analysis of conflicting objectives and mitigation strategies

The term “Performance Gap“ is used to denote deviations between a building's planned and actual performances. We conducted an international literature search and identified more than 240 relevant references. Here we report our main findings. Currently, mainly the energy performance gap is discussed, which is neither properly standardized or regulated nor precisely defined. In our opinion, the performance gap discussion needs to be extended to the indoor environment and the operation expenses. A more differentiated approach must distinguish between individual buildings and entire building stocks where a statistical interpretation becomes unavoidable. We propose that the evaluation of the building performance should be based on thorough application of statistical methods. At the same time preventions of gaps require an integrated performance and risk management process, for instance through application of the “performance-based building design” and “integrated project delivery” approaches. For Switzerland, this is an invitation to experiment with alternatives to today's economic and contractual practice.