A Comparative Analysis of NZEB Energy Performance Requirements for Residential Buildings in Denmark, Estonia and Finland

Direct comparison of building energy performance levels between countries is usually not possible due to differences in climatic conditions, calculation methods, primary energy (PE) weighing factors and input data. This paper aims to analyse performance requirements and calculation methodology for residential Nearly Zero Energy Buildings (NZEBs) in Oceanic and Nordic climate zone countries according to European Commission (EC) recommended values, focusing on Denmark, Estonia, and Finland. Performance levels for each country are compared with European Commission (EC) recommended values (EU 2016/1318) using normalization and benchmarking through detailed computer simulations. The study is based on two representative buildings: a Danish single-family house and an Estonian apartment building, both designed to meet national NZEB requirements. The buildings were modelled using national and standardized (EN 16798-1:2019) methodologies, including country-specific climate and input data. The simulated performances were compared with EC threshold values, modified, and re-calculated to meet the NZEB PE targets of each country. To match the recommended energy performance, on-site renewable energy production using photovoltaic panels was increased or decreased accordingly. Results show that Estonian requirements for NZEB fulfil the EC NZEB recommendation. In the warmer, Oceanic climate zone it was however impossible to fulfil EC NZEB even with Estonian NZEB. This indicates that PE recommendations are too strict for colder Oceanic locations, represented in this paper by the Copenhagen climate.