A long-time study on improving energy efficiency of buildings came to a surprising result in Munich last week. More than 7 years ago the Munich building society GEWOFAG fitted 6 exactly identical multi-storey building with various different energy saving technologies to find out which was the most efficient. The stunning result: installing a simple mechanism that automatically switches off radiators in a room when the windows are opened is more efficient, cheaper and almost maintenance free, compared to more traditional approaches like ramping up building insulation. What are the indications of this research for building laws?
The Munich project started in 2009. It´s purpose was to find out how energy efficient buildings might be optimized and how users of buildings influence these efforts. The study looked into energy consumption of the 6 buildings as well as into maintenance costs and the failure proneness of the different energy saving systems to find the most efficient solution. Crucially, the user behavior of tenants was also monitored and factored in.
The 6 buildings were respectively fitted with a window contact that automatically switched off radiators in a room where windows are open or improved wall insulation or a ventilation system with heat recovery or wall-radiators or the ability to regulate heat electronically in the individual rooms. In addition there was one reference building.
In all three categories, the building with window contacts outperformed all other solutions. This means more energy can be saved by fitting buildings with these (comparably) cheap contacts, than, for instance, by expensive wall insulations. This study shows that current laws on energy efficiency, which focus on insulating buildings and make certain insulations obligatory in many countries do not further the most efficient option to save energy. The executive summary of the study is available at: https://www.ris-muenchen.de/RII/RII/DOK/SITZUNGSVORLAGE/4001844.pdf (only German language version).