District heating is the most common form of heating in Finland. It is a natural and reliable heating method in densely built areas. District heating has been produced in Finland since the early 1950s.
It is available in almost all towns and population centres. About 2.6 million Finns live in houses heated by district heat. District heating accounts for almost 50 per cent of the total heating market. The more densely built the area is and the larger the buildings, the more economical district heating is. Almost 95% of apartment buildings and most public and commercial buildings are connected to the district heating network. In single-family houses, a good 7% of the heating energy comes from district heat. In the largest towns, the market share of district heating is more than 90%.
The superior energy efficiency and environmental compatibility of district heating are based especially on the fact that district heating utilises heat energy generated in electricity production (combined heat and power generation) and as waste heat from industrial and other processes, etc., which would otherwise be wasted.
District heating fuels include natural gas, coal, peat, and increasingly wood and other renewable energy sources, such as biogas. Almost 80% of district heating is obtained from heating plants producing heat and electricity (CHP, cogeneration), as surplus heat from industry, or from biogas combustion in landfills.
Customers receive heat through the hot water circulating in the district heating network. The hot water in the supply pipe releases heat to the heating and water networks of the house with the customer’s heat exchanger. District heating water does not circulate in the domestic heating and hot water networks of the houses.