SFOE study: Energy consumption of certified buildings often too high
Energy consumption planning values according to Minergie and statutory building standards are often exceeded in reality in certified buildings - especially in apartment buildings. The area of operational optimization is therefore to be further developed.
For the first time, the Swiss Federal Office of Energy (SFOE) conducted a broad-based performance review of building with Minergie and statutory building standards. The study now available determined the actual energy consumption of around 200 different buildings. The result: the planning values only partially correspond to the energy consumption values in practice. This discrepancy is particularly striking in the case of new or converted apartment buildings.
The aim of the SFOE study was to examine the extent to which the planning values correspond to the actual, measured energy consumption values. The annual energy consumption in relation to the energy reference area of 214 properties that were built or renovated according to Minergie, Minergie A and Minergie P or statutory building standards was examined. The planning values were met to varying degrees in single-family houses and conversions, depending on the building category and standard. The majority of new and converted multi-family houses did not comply with them.
The authors of the study cited functional and adjustment problems as well as low heating efficiency as possible reasons for the numerous instances in which the design values were exceeded. In some buildings, however, less energy was consumed than the planned values. The large deviations of the planning values from the actual energy consumption are therefore also strongly due to the behavior of the building users.
Great satisfaction
The study also examined qualitative aspects of Minergie: The satisfaction of building owners who build according to Minergie is high, as an online survey of architects and building owners shows. Almost four out of five building owners would build to the same Minergie standard again today. According to the survey, the Minergie quality label serves as a sales argument. However, discussions with 50 experts have shown that Minergie building standards have lost their edge because technological advances have also been made in conventional building - not least thanks to Minergie.
In another online survey, users of Minergie properties showed themselves to be satisfied in terms of sound insulation, protection from drafts and protection from cooking odors, but often found the air in their rooms to be too dry in winter. The interplay between energy efficiency and user needs still needs to be analyzed in more detail.
Based on the results, SwissEnergy intends to further develop and support the area of operational optimization together with the Swiss Society of Engineers and Architects (SIA), the building technology associations and other market players.
(BFE)
