Problems of processing of the building energy performance certificate in case of sale and lease of existing buildings

This paper deals with a fundamental change in the Energy Management Act, which from 2013 introduces in some cases an obligation to process the Building energy performance certificate even for existing buildings. One of these cases is sale or rental of the building or unit. The paper summarizes an issue of evaluation of existing buildings, and points to facts that may adversely affect the quality of certificate processing and the reality of its information value. It follows up existence and usability of a project documentation of older objects and necessity of correct identification of materials used in the building including stating sources, which may be the cause of incorrect identification of materials. An example in this paper points to the importance of their correct identification from the point of view of thermal evaluation of structures that enter into the certificate. This paper briefly outlines possible impacts of the use of certificates for older construction on real estate market