The German energy decree was tightened by about 30% in the middle of 2009. Yet, several German cities, like Nürnberg and Düsseldorf, are fixing even tighter energy performance requirements for new buildings and major renovations for existing buildings owned by the city, or to be built on the city's ground. Thus, they are following an approach that has been realised by the city of Stuttgart for several years now. Since 1998 Stuttgart's energy decree requires of builders that buy property from the city, but also of the city's own new buildings, to fulfil energy performance requirements that go about 20-40% beyond national requirements. The city's energy decree is updated with every new German energy decree on the basis of detailed analyses of energy saving measures and their cost impact.
Further information on communities' energy performance requirements can be found (in German) at the following links.