District heating plays an important role as energy carrier in many European cities, particularly in Sweden. This paper describes the reasons for the rapid development of district heating in Sweden since 1950. Almost exclusively, hot water, which offers many advantages over steam, has been chosen as the heat-carrying medium.

One important reason for hot water district heating is that it offers the possibility of using different primary energy sources without costly changes. This point is highlighted with examples from the city of Uppsala from which some general conclusions can be drawn.