The investment concerns a deep thermal modernisation of the public utility building – the City Hall, located at ul. Katowice 45 in Czeladzi. The scope of the project shall include: a) insulation of the floor on the ground, b) warming of the walls of cellars, exterior walls and ceilings, c) altering the layout of the windows at the entrance of the building and full replacement of the window joinery, d) replacement of the door joinery, e) replacement of the heat source for central heating, f) modernisation of the internal installation of central heating (g) replacement of volume heaters for the preparation of central heating (h) installation of mechanical ventilation systems with repair of heat in the session room. The project, concerning a building with a total usable area of 3188.97 m², leads to an increase in energy efficiency by approx. 81,47 % and contributes to a reduction of CO2 emissions from 231,47 t/year to 68,34 t/year, i.e. by 163,13 t/year. (70.48 %).