The impact of the weather data file on the energy performance certificate, the case of Norway

Energy Performance Building Directive (EPBD) ask the Member of States to develop a mandatory energy labelling scheme for new and existing buildings, which should include a label rating of the energy efficiency of the building and a list of recommended energy saving measures. The label will provide prospective buyers and tenants of a building with correct information about the energy performance of the building to compare with other options. However, some countries use only one or a limited number of weather zones. In a country like Norway, with significant variations in weather conditions between locations, this is likely to cause a deviation when comparing with the reality. This study aims to present the implication of using only one weather zone in Norway. The method used is based on the comparison of three types of weather files. The first one is used in the labelling system, which is a typical year, while the others are typical reference years from the local site from different providers. The results show significant differences in energy consumption, savings and labelling ratings when applying files with local weather data instead of the official weather data file used in Norway.