Nordic Thermal Mass – Effect on Energy and Indoor Climate


The importance of the thermal performance of buildings has increased due to e.g. the implementation of the Energy Performance Directive of Buildings. In this context energy certification systems of buildings will also require the calculation of energy consumption of buildings in future. The fact that the thermal mass of buildings decreases total energy consumption, is well known, but the amount of this effect depends on many assumptions and values used in the calculations. During this project it has been collected the best available Nordic knowledge around the table to develop a Nordic consensus about the questions studied. It’s important that we have in Nordic countries enough knowledge to be in the forefront in order to get our views included in the European standardisation. The thermal mass of buildings has a clearly positive effect on energy consumption and indoor climate. However, the buildings have to be designed cleverly to be capable to utilise possibilities for smaller energy consumption and better indoor climate. This project was a co-operation project with research institutes of Nordic countries. There were used six different energy calculation software’s, whose results were compared with each other and with one program based on the European standard EN 13790, Thermal performance of buildings – Calculation of energy use for space heating and cooling. The main author of the report and the collector of the results was Timo Kalema from Tampere University of Technology.