Results of long-term energy efficiency monitoring of test buildings under real climatic conditions

The calculated energy efficiency and specified physical properties of building materials may change significantly during the initial years of a building’s operation under real climatic conditions. Five small test buildings with different wall assemblies were built in Riga, Latvia to compare different building construction characteristics under Latvian climate conditions. The heating energy consumption, thermal transmittance, air relative humidity and other important energy efficiency and environmental parameters have been monitored since late 2012 when the test buildings were constructed. Changes in characteristics have been observed and widely analysed. The monitoring results show significant differences in the initial moisture content of building materials and in U-value, and therefore, heating energy consumption and comfort conditions in the buildings. The differences between calculated and measured values are remarkable, even after two heating seasons. Parallel to the research on energy efficiency during heating seasons, an overheating risk analysis for the buildings during summer was also performed, showing the role of thermal mass on thermal comfort. An analysis of measurements made under real climatic conditions allows consideration for the difference in calculated and actual properties, for an estimation of the buildings’ real energy efficiency.