District heating

Heat is generated in a thermal plant and is distributed through a network of pipes to industrial and commercial premises, apartment blocks and single-family houses in the town. Illustration: Bo Reinerdahl

In a district heating system, entire towns or parts of towns are interconnected with a common pipe network, and the heat distributed is generated in a central boiler station or in a central combined heat and power (CHP) generation plant that delivers both electricity and heat.

District heating substation

If you are connected to a district heating network, heat is supplied to your house through underground pipes. A house connected to a district heating system needs a district heating substation. This includes everything you need for heating and hot water, including two heat exchangers, one of which is for hot water and the other for heating.

The Swedish District Heating Association certifies district heating substations. Certification means that the substation has undergone impartial examination of performance, operation and execution.

District heating plant

Heat generation in large boilers is more efficient and more environment friendly than individual home-owners firing their own boilers. Professional personnel in a district heating station keep a check on the operation. Waste heat from industrial plants or waste water can also be used in the district heating system. Combined heat and power (CHP) stations generate both heat for district heating and electricity. Combined heat and power generation is a very efficient way of using fuel.

Biofuels

A large proportion of the heat for district heating in Sweden is now generated by biofuels such as wood chips and pellets. This is done under controlled and environmentally friendly forms. On average, the emissions of carbon dioxide are therefore ten times higher in an oil-fired domestic boiler than in a district heating plant. Biofuels are obtained in the form of residual products from plants such as sawmills and other woodworking plants, and from unused branches and treetops in forestry.

Costs

The cost of connecting your home to the district heating system vary depending on the municipality in which you live, and the price of heat may also differ. The fact that prices differ is due to local conditions, the fuel used by the district heating company, and the density of customers that the district heating company serves.

The heat consumption charges for district heating are generally somewhat lower than the cost of electricity and oil. Since the price of both electricity and heat from the district heating system consists of many different components, it may be somewhat complicated to compare the two alternatives.

As an example, the price of domestic electricity can change when you switch from electric heating to district heating – downwards since you can manage with a lower main fuse rating and upwards due to the tariff change. Get in touch with your district heating supplier for a more accurate calculation.

Advantages and disadvantages

+ often a lower price than oil and electricity
+ district heating plants often use renewable fuels
+ little space needed
+ requires no work input
+ low emissions of environmentally harmful substances

- no possibility of switching to a different supplier
- changes in ventilation in a house with natural draught ventilation if the house previously had oil, wood or pellet firing.