How to compare energy performance requirements of Japanese and European office buildings

This study applied the normalisation method that enabled to compare the energy performance of buildings from European and Japanese climates. A reference office building was simulated with national input data and weather file in order to estimate the thermal conductance of building model and heating degree-days for a reference climate. Based on simulated results, economic insulation thickness and thermal transmittance of windows for all climates were determined. A reference office building corresponding to Japanese ZEB Ready performance was moved with this method to Estonian and French climates. The results compared to national NZEB requirements and EC NZEB Nordic and Oceanic recommendations. It was found that the Japanese ZEB Ready building configuration with air source heat pump was very close to EC NZEB recommendations. However, in the case of district heating and gas-boiler heat sources, it was needed to improve Japanese ZEB Ready building configuration in order to meet EC NZEB recommendations. Estonian NZEB requirement met EC recommendation with both heat sources, but French NZEB requirement was much less ambitious.