Thermal Insulation Ordinance 1977
The German Thermal Insulation Ordinance ("Verordnung über energiesparenden Wärmeschutz bei Gebäuden (Wärmeschutzverordnung - WärmeschutzV)") was the first ordinance based on the German Energy Saving Act of 22. July 1976. It was issued on 11 August 1977 and was effective by 1 November 1977. Up until this point, there did not exist any regulation subject to public law for energy saving thermal insulation on buildings in Germany (just like in most other countries) but only technical standards (DIN 4108) concerning this matter.
As a criterion to determine in how far energy certificates based on energy consumption may be issued for buildings with less than 5 accommodations, the compliance to the requirement level of the Thermal Insulation Ordinance 1977 is consulted in § 17 section 2 EnEV 2009 (as well as in EnEV 2007). In order to asses this question, the Thermal Insulation Ordinance 1977 itself can be consulted, otherwise a simplified assessment based on the regulations for data acquisition and data usage in the building stock (here: section 7) can be conducted.