The energy efficiency of district heating (DH) systems can be increased by not only optimising the operational parameters of existing systems but also by integrating new elements into such systems. The paper recommends the installation of a high-temperature heat pump in the return water pipe system of a heating network in order to cover a part of the consumer's heat load. The authors provide a diagram for calculating the integration of a heat pump into the DH system and have also performed modelling in order to determine the changes in the network parameters over the course of a heating season if the heat pump has been working at a nominal capacity. The calculation model contains a system of equations that describes the mass and energy balances of the elements as well as changes within them over the course of a heating season.