Within the SQUARE project a general quality assurance (QA) system to ensure energy efficient renovation of multi-family housing with good indoor environment has been developed. The overall objective of the SQUARE QA system is to ascertain that all predefined requirements on indoor environment and energy performance are achieved. It is based on a policy for retrofit actions defined by the organisation and includes all the steps in the renovation process, i.e. planning, design, construction and management phases. The report of the QA system and documentation of applications in pilot projects are now available for download.