The key ability of the future district heating system is to operate at lower network temperatures. The aftercooling system reduces the return temperature from the building, and this is often a precondition for being able to reduce the district heating supply temperature. Lower network temperatures make it possible to utilise low temperature surplus energy sources that otherwise would be wasted or would require a temperature lift by e.g., a heat pump. Further it reduces the thermal distribution losses from the district heating network. The potential for district heating return temperature reduction is 4-8°C on yearly level for typical buildings, which is significant.