Fuels produce heat when burned. A fireplace warms up the room around it when wood is burned there. The heat radiates into the room in the form of radiation, as well as by conducting through the air around it. When the fire dies out, the temperature of the room decreases rapidly. A regular fireplace wastes a lot of heat.

A heat-storing fireplace radiates heat even after the fire inside it dies out. The heat is conducted into the rocks and tiles of the fireplace. They release heat into the air around them slowly. By doing so, the heat-storing fireplace produces more heat.


A heat-storing fireplace uses energy more efficiently than an open fireplace.

In central heating units, a fuel such as wood is burned in a single kettle. One fire is used to heat up a complete household. Heat is conducted from the fire into water, and the hot water is directed into the rooms of the building through pipes. Smaller heating units then conduct heat into the air. 

Central heating units can also be used to heat multiple houses. These kinds of heating units are usually larger and use oil as their fuel. The heat produced by the central heating unit is transmitted into the houses through water or steam pipes. 


Central heating units come in different sizes.

When whole neighborhoods and towns are heated by burning a fuel, we are talking about direct heating. Direct heating takes place in power plants, where natural gas, coal, peat, waste or wood chips are burned. The heat is then transmitted into neighborhoods and buildings through water or steam pipes. At the same time, the power plants can also produce electricity.


Fuels can be burned in power plants. By doing so, it is possible to provide heating to whole neighborhoods or even cities.