The following kinds of requirements for existing buildings can be discerned within the Energy Saving Ordinance (EnEV):
- Conditional requirements
If the owner of an existing building makes certain alterations determined in Annex 3 of the ordinance to shell components belonging to heated or cooled space (mainly: refurbishment measures), requirements concerning the resulting heat transmission coefficient have to be met by the part of the surface that is covered by the measure. This does not apply in cases when the coverage of measure does not exceed 10 % of the total surface covered by this kind of shell component on the whole building.
[more about conditional requirements]
- Mandatory upgrade requirements
In certain cases mandatory upgrades of certain parts of the building (exchange of old boilers, insulation of certain pipes, insulation of top ceilings, installation of certain control devices in heating- and AC-systems) are required by the ordinance independently of measures.
[more about mandatory upgrade]
- Requirements in case of extensions
In case of extensions, requirements for the new parts of the building are set up within the ordinance in a differentiated manner.
[more about extensions]
- Requirements in case of new installation or add-ons of heating-, DHW-, ventilation- and AC-systems
Concerning the installation of building services (heating-, DHW-, ventilation- and AC-systems) the ordinance does not differentiate between installation in new buildings and installation in existing buildings. Certain minimum requirements concerning control devices and insulation of these systems have to be met.
This also applies to the new parts in case of extensions / add-ons of these systems. Furthermore, certain requirements have to be met in some cases of refurbishment (e. g. exchange of central units of ventilation- and AC-systems).
These requirements are different concerning their range of application an can be found in §§ 14 and 15 of the EnEV.