The complex of the buildings KT4 KT5a KT5b and KT5d of the General Hospital of Thessaloniki, Georgios Papanikolaou, has a total area of 2075379 m and an area of heated spaces of 1781022 m. The unheated area concerns areas of the basements of the thermal stations of the mechanized warehouses of abandoned spaces and various areas for the service of the warehouse building on the rooms of KT5a and KT5b. Based on the energy inspection carried out and the EPC Energy Performance Certificate, the building in its current condition was classified in category E. The interventions will result in the energy upgrade of the complex from Class E to Class B as reflected in the attached Energy Performance Certificate.