More than half of the existing hot water network of the central heating system of the city of Zagreb was built in the period when the technology of canal laying of hot water was used, which led to increased heat losses and an increased number of interruptions in the supply of heat energy. The project, in the period until 31.12.2026, is planned to replace 25.406 km of 66.182 km of the most critical sections of the hot water network with the aim of increasing the energy efficiency of the heat system and the reliability of the heat supply in the city of Zagreb. The project in question represents the second phase of the ‘Revitalisation of the hot water network in the City of Zagreb’. As part of the first phase, in the period until 31 December 2023, the exchange of 40,776 km of 66,182 km of shares was carried out.