The subject of the project is a deep comprehensive energy modernisation of the Hydromechanics building of the Gdańsk University of Technology located at 11/12 Narutowicza Street in Gdańsk. Today, the building is characterised by high demand for heat and peak power due to poor thermal insulation of building bulkheads and increased room ventilation. It is in poor technical condition and requires extensive repair work. The material scope of the works is entirely due to the energy audit carried out and includes the following tasks: —Construction of a heating node on the basis of plate exchangers in the room of the former heat distributor. —Introduction of automatic regulation of heat source. Installation of a two-tube installation made of copper pipes. Insulation of heating hoses. —Assembly of convector and channel radiators equipped with thermostatic valves. —Assembly of the technological heat system from black steel pipes supplying air curtains located above the entrances of the building and ventilation panels. —Replacement of all windows in existing antique box windows for an ordinary external glass and an internal three-ply two-chamber window. —Exchange of external doors to energy-efficient according to the recommendations of the Monuments Conservator. —The warming of the outer walls from the inside by means of climatic plates. —Making moisture insulation of the foundation walls to avoid damp walls in the mundane zone. —The warming of the roof drops over the heated rooms between the rafters with mineral wool. —Replacement of roof covering with carp tile. —The warming of flat ceiling with Styrofoam. —The warming of the ceiling under unheated attic with mineral wool. Construction of central heating installations made of plastic pipes and fittings. Insulation of heating hoses. —Assembly of mechanical ventilation system with heat recovery – rotary exchanger. Installation of ventilation centers.