The project concerns the energy upgrading of the building of the Kalyves Exhibition Centre, the Municipality of Polygyros. The building currently exhibits reduced thermal comfort conditions throughout its operation, as well as significant energy consumption, placing it in category D of the Buildings’ Energy Efficiency Regulation (KENAK). This project provides for interventions for the energy upgrading of the building, including work on the housing of buildings (heat of faces and roof, replacement of windows), modification of the heating installation of the complex (application of a hybrid system with boiler and air-water heat pump), replacement of boiler, replacement of non-functional heating bodies, installation of automatic heating control system, replacement of luminaires by a new LED type, the installation of the PPC’s photovoltaic system and the energy interface. Upon completion of the project, the building is expected to be classified as category A+ of KENAK.