The project concerns the energy upgrading of the building complex of Polygyros High School, the Municipality of Polygyros. The school complex consists of 2 buildings, which are classified in category H of the Energy Efficiency Regulation (KENAK). During the implementation of this project, interventions are envisaged for the energy upgrading of buildings, including interventions on the housing of buildings (heat of the faces and roof, replacement of windows), modification of the heating installation of the complex (application of a hybrid system with boiler and heat pump), boiler replacement, replacement of non-functional heating bodies, installation of automatic heating control system, replacement of metering bodies by a new LED type, and the installation of PPC connectors. Upon completion of the project, the buildings are expected to be classified in category A and A+ of KENAK.