The requirements for the building envelope and the building technology are constantly increasing. There is a lack of easily reproducible and in practice manageable measurement and analysis methods to control the quality of construction. The aim of this annex is to provide the methodological basis for an on-site (in situ) assessment of the actual energy efficiency, with a focus on practicable characterization procedures (in the inhabited state). The Austrian contribution examines possibilities for using "already existing" data sources, such as Building automation or smart meters, and methods for identifying energetic building behavior with a reduced database. Identification methods with a focus on quality assurance in highly efficient buildings will be tested on a real object.