The project concerns the implementation of appropriate measures for the integrated energy upgrading and integration of Renewable Energy Sources (RES) systems in the Youth Hostel of the Municipal Community of Petrousa of the Municipality of Prosotsani, aiming at achieving the optimal energy and environmental footprint and the emergence of the Hostel as a model building. Following the implementation of the planned interventions, the classification of the building is expected at least in category B of the Energy Efficiency Regulation (KENAK), with energy savings of 66 % and a reduction of the environmental burden of 282.6 t of CO2 per year.