Conditional requirements for energy modernisation (§ 9 EnEV)
Apart from retrofitting obligations, additional energy saving measures for existing buildings are only required by law in the case that certain measures of major renovation are carried out anyway (conditional requirements).
§ 9 EnEV sets energy-related requirements for measures of renovation according to Annex 3 and for internal and external extensions of buildings. If major measures for a building component are necessary or planned for other reasons, e.g. for maintenance reasons or public safety obligations, the renovated parts of the surface have to meet energy standards ("conditional requirements"). These requirements in every case only apply to those parts of the surface that are subject of the modernisation measure carried out anyway.
The component requirements according to § 9 clause 1 sentence 1 EnEV in conjunction with Annex 3 EnEV have to be met whenever certain measures are carried out. The relevant measures connected to conditional requirements are listed in a conclusive enumeration in Annex 3 Numbers 1 to 6 – sorted by respective fabric component.
In cases of modernisation measures concerning
- outer walls,
- elements of the roof,
- walls separating from unheated space or ground and
- ground elements separating from unheated space, outside air or ground
the conditional requirements are not valid for components constructed or refurbished with respect to legal requirements after 31st December 1983 (getting into force of the 2nd Thermal Insulation Ordinance). The reason for this limitation of validity is of economical nature; the issuers of the ordinance refrained in these cases from requirements because the difference between the energetic status before and after the measures cannot always guaranty a sufficient amortisation.
On the other hand, external and internal extensions are subject to requirements in § 9 clause 4 and clause 5 EnEV.
According to the so-called "Bagatellregelung" in § 9 clause 3 EnEV, the requirements are not compulsory when the partial surface that is subject to the measure does not exceed 10 % of the total surface of the fabric component in question for the specific building (for further information see Auslegung zu § 9 Absatz 3 - German language only -).
Proof of the building’s overall efficiency instead of component requirements
Instead of meeting component requirements for every single relevant alteration of shell components it is possible to prove that the whole building does not exceed 140% of the requirements set up for new buildings (on the level valid from 2009 to 31th December, 2015). In course of this proof, simplifications given in the official bulletins about data recording and – use in building stock can be applied (especially for those parts of the building that are not subject to alterations).
Coupling principle, applications for exoneration
Conditional requirements (like most requirements of the EnEV) can be subject of exonerations granted by the authorities in charge (according to regional legislation), especially if in the individual case a suitable amortisation cannot be expected.
According to the coupling principle, in case of conditional requirements only the energy-related additional costs shall be included in the assessment of cost effectiveness, as the remaining refurbishment costs would have arisen regardless of the energy modernisation. In consequence, only the energy-related additional costs can be subject of exonerations. Exoneration shall be granted as far as an undue hardship is given. If an application for exoneration is based on a lack of economic feasibility, the exoneration may be only partial and exclude economically reasonable parts of the measure (e.g. an insulation with a lesser thickness than required).