IEA EBC Annex 71 - Building energy performance assessment based on in-situ measurements

The building sector accounts for about 40% of total final energy use and harbours enormous potential to save energy and reduce CO2-emissions in a cost effective way (Economidou, 2011). In order to reduce the energy use of buildings, policy makers impose ever more stringent requirements with regard to energy performance of new buildings and renovated buildings, and the use of renewable resources. Most compliance checks and labelling of the energy performances of buildings are done in the design phase by calculating the theoretical energy use. But, despite regulation and policy enforcements, monitoring of actual energy performances reveals in many cases a significant gap with theoretically designed targets (e.g. Bell et al., 2010, Hens et al., 2007). Sources of deviation between the actual and expected performances can be attributed to the design phase (limitations, inaccuracies and assumptions in the numerical models used to predict the energy performance), the construction phase (quality of workmanship and differences between assumed and actual installed materials, components and systems) and the operation phase (ill functioning of systems and/or no match between assumed and actual building usage). The currently observed performance gap, in combination with the increasing integration of innovative systems such as intelligent elements, low energy technologies, active solar systems, etc., accentuate the need to develop reliable methods and procedures that can be applied on site to assess the actual performance of buildings.

The project is supported by EUDP.