The subject of the project is the replacement of existing high-loss steam lines with new hot water pipes in the pre-insulated design. As a result, losses will be reduced by approximately 2/3 from the original value. The project consists of (a) the replacement of the backbone pipes of the steam pipelines North, South and East, (b) the strengthening of the thermal and pumping power of the source exchanger and the replacement of transfer stations at customers, (c) installation of optical interconnections, modifications of the control and operational optimisation system.