Nearly-zero energy buildings in Denmark—New requirements and challenges for residential energy efficiency in Building Class 2020

The executive order on building regulations 2018 (BR18) issued by the Danish Ministry of Transport, Building and Housing came into force at the end of 2017. In this order, the new energy class of buildings—Building Class 2020 (first released in the amendments of BR10) was finalized. The Building Class 2020 was prepared to meet the requirements of the EU Directive on the energy performance of nearly-zero energy buildings. The new Danish energy class of buildings requires to decrease the energy consumption of HVAC plus domestic hot water down to 20 kWh/(m2·a). This paper briefly presents the requirements of the Building Class 2020 for residential buildings on architecture, building envelope, windows and doors, air tightness, HVAC and daylight, etc. Some challenging issues to meet the requirements of the Building Class 2020 are discussed.