The project concerns the implementation of the appropriate measures of integrated energy upgrading and energy saving, with the incorporation of Renewable Energy Sources (RES) systems in the building of the Municipal Gymnasium of the Municipality of Prosotsani, with a total area of approximately 1,783,31 sq.m., which presents insufficient thermal insulation protection, while its electromechanical installations are characterised by low performance factors and high consumption, thus not achieving the desired conditions of thermal and visual quality. The objectives of the project are a) the achievement of the optimum energy and environmental footprint of the building, b) its classification at least in energy category B of the Energy Efficiency Regulation of Buildings (KENAK), with an estimated primary energy saving value of 742.3 KWh/m² and a reduction of CO2 emissions by 239,81 Kg/m², and c) the emergence of the Gymnasium as a standard building.