Residential construction needs its own standards, not those of an office building.
The Sustainable Buildings rating system, or BNG for short, is offered by the Bau-Institute for Resource Efficient and Sustainable Building, BiRN, for residential buildings with more than five units, as a specialized alternative to broader systems. Since 2021, BNG certificates have been part of the QNG seal catalog; the criteria have been harmonized with the state quality seal. For developers of multi-storey residential construction, the system can be a more direct route to eligibility, compared to a system that contains many criteria that are of little importance for pure residential construction. The system (BNK) can be used for small residential buildings with up to 5 residential units.