Mixed use buildings
In principle, all requirements apply to the building as a whole. This generally includes the issuing of energy certificates as well.
If a building contains residential- as well as non-residential uses, in several cases determined in § 22 EnEV the building should be treated as two separate buildings; this division includes the provisions about issuing energy certificates as well. The following cases have to be distinguished:
Predominant residential use
If a building predominantly is a residential building and the parts that are not for residential use are
- with respect to their technical facilities
considerably different from the residential parts and
- cover a not negligible part of the useful floor area of the building,
these parts of the building are treated separately as a non-residential building. All three of the aforementioned conditions have to apply. According to current interpretation partitions of up to 10 % are "negligible". Furthermore, the broad definition of "residential use" has to be taken into account: several types of dormitories and institutional homes (e. g. for elderly or handicapped persons) are considered as "residential buildings".
Predominant non-residential use
If a building predominantly is a non-residential building and the parts that are for residential use cover a not negligible part of the useful floor area of the building, these parts of the building are treated separately as a residential building. According to current interpretation partitions of up to 10 % are "negligible".