The ImmoGap project investigates the so-called performance gap for multifamily buildings. It contributes to a better classification and a clearer definition of the term "performance gap". As a first step, a literature study on this topic was carried out. In principle, the "Performance Gap" is understood as an additional consumption of heat or a failure to meet energy benchmarks. The term "Performance Gap" suggests that a desired service is not provided. This is critical, because there are several reasons why a building consumes more energy than originally planned. In the project, the heating energy consumption of 65 multifamily buildings was compared with the heating demand according to SIA 380/1 (energy certification). In contrast to other studies, the project team was able to access measurement data with a very high time resolution. On average, the heat demand calculated with standard use is exceeded by 44%. Four of the buildings have an additional consumption between 100% and 115%. Detailed investigations with simulations and measurements show that the additional consumption can largely be explained by the user behavior regarding shading, ventilation and room temperature, which deviates from the norm. If the observed user behavior were already used in the demand calculation, the examined buildings on average would not show any "performance gap". A comparison between space heat consumption and space heat demand according to the energy certificate (SIA 380/1) is therefore to be regarded as critical, since the energy certificate is not intended as a predictive instrument but as a benchmark tool for the authorities. However, suitable comparison instruments for a larger pool of buildings are currently lacking. Due to developments in architecture (e.g.: larger windows) and the changed living habits of residents, it is recommended to investigate user behavior in more detail.
