The subject of the project is a comprehensive modernisation in the field of saving electricity, heat and water, together with the simultaneous use of RES installations in the building of Primary School No. 3 in Siemiatycze. The aim of the project is to improve the energy efficiency of the public utility building, i.e. the school building. The scope of the project includes deep energy modernisation through warming of external walls, warming of non-ventilated stropods over the gym and stairways and ventilated ceilings over the didactic part, window replacement, external door replacement, ventilation and ventilation with heat recovery supported by photovoltaic installation. In addition, the project assumes the modernisation of lighting, which will reduce electricity consumption in the building. The project is included in the strategy of the energy cluster listed in Annex 1b to the Territorial Contract for Podlaskie Voivodship i.e. The Siemiatycki Energy Cluster. Thanks to the project, it will be possible to reduce emissions of greenhouse gases and other pollutants into the atmosphere (the percentage change in CO2 emissions from the base year will be 59.73 %), reduction of heating and electricity costs will reduce the operating costs of public institutions and increase energy savings in the public building (quantity of electricity saved 235.25 MWh/year, amount of heat saved 4173.18 GJ/year). The project will improve energy efficiency by 61.37 % (i.e. 2096811,11 kWh/year – Reduction of annual primary energy consumption in public buildings (CI 32). The target group will in particular be pupils and employees of SP No 3 in Siemiatycze and other users of the facility, most frequently using the public utility building. The group of indirect beneficiaries should also include the entire local community, which will be able to use the facility.