The main objective of the QUALICHeCK project is to respond to the concerns regarding the reliability of Energy Performance Certificate (EPC) declarations and the quality of the works. In order to analyse the situation in the ground, compliance assessment studies were conducted in 9 focus countries. Five of the new field studies (Austria, France, Greece, Romania, Sweden) analysed energy performance compliance and EPC input data quality by site visits, check of design documentation and new energy and EPC calculation to compare actual and reported energy performance. Three studies (two in Belgium, one in Cyprus) worked with transmission characteristics including quality framework for cavity wall insulation and input data on window thermal performance and U-values compliance. One study (Estonia) was devoted for summer thermal comfort, including temperature measurements, check of design documentation and temperature simulations based on actual solutions checked by site visits. Reliability of EPC issued with different calculation methods was studied in Spain.