Abstract This paper aims to provide an overview of the costs and benefits of preparing existing space heating systems for low-temperature district heating. Necessary heating system improvements were assessed based on previous work carried out on the topic. This included evaluating the necessity of installing larger heating elements and improving heating system control. The costs of the identified heating system improvements were then estimated and compared with the savings achieved if district heating temperatures were lowered, from the perspective of both the total Danish energy system and the individual district heating customers. The investigations resulted in simple payback times of 1.2–4.3 years from an energy system perspective and 0.3–18.7 years for an individual district heating customer. The current study thus indicates that it is economically feasible to invest in an improved heating system control to enable a reduction in the district heating return temperatures.