Abstract Purpose The production and construction of buildings cause significant environmental impacts besides those arising from their operation. Recently, some European countries have started introducing life cycle assessment as a mandatory calculation method for new buildings, and it is foreseen that by 2030 this will be done in every member state, at first without any legal minimum values. Methods Extensive databases on the embodied impacts of buildings, which would be needed to support setting the baseline impacts, are still missing. This paper proposes an approach for determining bottom-up reference values. A large building sample is generated describing “technically feasible” new buildings. Instead of analysing a few typical buildings, the main parameters describing a building are determined and the ranges are defined that these parameters typically take. With the variation of these parameters, a large building sample is generated, and the surfaces and built-in material quantities are determined for typical construction solutions to assess environmental performance. Results and discussion The method is demonstrated by calculating the reference embodied benchmark values for new residential buildings in Hungary. The results show a baseline embodied Global Warming Potential of 9.5–15.5 kg CO2-eq/m2/yr for single-family houses and 9.1–14.3 kg CO2-eq/m2/yr for multi-family houses. Conclusions This method is suitable for estimating the environmental impact of typical new buildings in countries where a large pool of real building data is not yet available.