EffizienzhausNiveau

Effizienzhausniveau is a German term describing the energy efficiency level of a building according to standardized criteria, primarily used in the context of KfW financing programs. The niveau is expressed as a number after "Effizienzhaus," such as 55, 40, or 70, and indicates the building’s allowed energy consumption relative to a reference building. Lower numbers denote higher energy efficiency. In practice, an Effizienzhaus 55, for example, must achieve at most 55 percent of the energy demand of the reference building, measured as primary energy or final energy depending on the program.

The measurement is carried out using standardized energy performance calculations under applicable regulations (e.g., DIN EN ISO 13790, EnEV/GEG), which account for heating, hot water, and electricity for normal operation. The building envelope, heating systems (heat pump, solar thermal, condensing boiler), insulation, air leakage, and ventilation all influence the resulting niveau.

The concept is most widely used through the KfW Bank's "Effizienzhaus" programs, which subsidize loans and grants based on the achieved Effizienzhausniveau. Certification is performed by recognized institutes to verify compliance with the criteria.

Critique and limitations: While widely adopted in Germany, the system depends on standard assumptions and may not reflect real-use conditions; regional climate, occupant behavior, and the electricity mix can affect actual performance.