Usable building area
It is determined as follows:
- (heated building volume) [m³] = volume that is enclosed by the heat-transferring area A (determined according to EnEV 2009 , Annex 1 No. 1.3.1).
If the floor height h g is less than 2.5 m or greater than 3 m, the usable area of the building must be calculated as follows:
Energy reference areas in Switzerland and Austria
In Switzerland and Austria, the term energy reference area is used, which in residential buildings normally corresponds to the gross floor area ( including the surrounding walls). With storey heights of 3.125 meters, the usable building area is identical to the energy reference area on full storeys.