The housing sector is the largest energy consumer in the city of Suwałki, characterised by the highest CO2 emissions (35 %), as well as the high dynamics of changes in power sources to heat. The main objective of the project is a comprehensive energy modernisation of 3 historic tenement houses at ul. Tadeusza Kościuszki 18, 20 and 26 in Suwałki owned by the Municipality of Suwałki is improving the energy efficiency of these buildings, which will contribute to improving energy efficiency throughout the public sector. Output indicators: — number of energy-upgraded buildings – 3 pieces. — usable area of buildings undergoing thermal modernisation – 1398.09 m² – reduction of annual primary energy consumption in public buildings 778922 kWh/year, Results indicators – amount of thermal energy saved – 2010.36 GJ/year, – amount of electricity saved – 78.26 MWh/year. The implementation of comprehensive energy modernisation of 3 municipal multi-family residential buildings will result in a significant improvement in living conditions for 90 people. The thermo-modernisation activities undertaken under the project will aim to bring the facilities into line with existing regulations and standards. The heat protections used will allow to maintain the appropriate temperature inside the buildings. Implementation of the project over the long term will improve the quality of life and improve the living conditions of the inhabitants of the region by improving energy efficiency in the public sector and improving the environment by reducing emissions of harmful substances into the atmosphere. In parallel, construction and installation works will be carried out in the scope of horizontal insulation of external and internal walls in the buildings provided for modernisation and replacement of electrical installations in dwellings.