Brief expert opinion on the question of the further development or conversion of requirement systems and standards in the German Building Energy Act for new buildings and existing buildings, including economic feasibility studies for buildings.

Based on an analysis of the requirements for new buildings, this report lays the foundations for deriving an amendment to the German Building Energy Act (GEG). In addition, necessary secondary requirements for components or sub-segments of the building are derived; further methodological changes are made, for example, to determine the primary energy factors, the reference building process and the calculation logic; the procedure for evaluating economic feasibility is revised; and proposals for the further development of the GEG are elaborated.