What is the efficiency and capacity of a wood-burning fire or stove?

Whether you opt for a wood-burning fire or stove firstly because of the atmosphere, or also want to heat a room to a large extent, it is nice to know the efficiency you can expect. Moreover, it is important to determine in advance what capacity you need for heating the room.

The efficiency of a wood-burning fire or stove

The efficiency of a contemporary wood-burning fire or stove cannot be compared to that of a traditional open fire. An open fire achieves an average of only 15% efficiency, because the fire loses a lot of heat through the chimney and does not reach such a high temperature. A newer wood-burning fire or stove achieves an average efficiency of around 70 to 80%. Due to the lower temperature of an open fire, combustion is less complete.

In a wood-burning fire or stove, a higher temperature is achieved and combustion is cleaner and more efficient. The emissions from an open fire compared with a wood stove are also a lot higher. When both are used to heat the same room, the open fire has been shown to emit up to 15 times more CO2 than the wood-burning stove. For ​​particulate matter, the difference is even greater: an open fire emits up to 50 times more fine dust than the wood-burning stove.

The capacity of a wood-burning fire or stove

The capacity of a wood-burning fire or stove must match the space you want to heat. But there are also other factors that you would do well to consider. Firstly, determine exactly what you expect from the wood-burning fire or stove. Is it primarily an atmospheric element for the occasional evening of enjoyment? Or will the fire or stove play an important role in heating your home? If heating is the main goal, the fire or stove needs more capacity than when atmosphere is the primary factor.

The consequences of too high a capacity

If you have a wood-burning fire or stove that has too much capacity for the room, the room will soon become too hot, so you cannot allow the fire to burn at full capacity. This, in turn, results in combustion not being sufficient, creating more odour and additional pollution in the chimney. That is why it is important to choose a fire with the right capacity range.

The amount of logs on the fire determines the capacity. A large fire that is filled with a few blocks does not have ideal combustion. That is why it is better to make a smaller fire and let it burn thoroughly. However, if the capacity is too low, you run the risk that the fire or stove will not heat the room adequately. This is especially annoying if the fire or stove has an important function in heating your home. Pay plenty of attention to choosing a fire with the right capacity.

Calculating the required capacity of a wood-burning fire or stove

Calculating the required capacity of a wood-burning fire or stove is done in a number of steps.

Calculate the volume of the room

First, calculate the volume of the space that you want to heat with the wood-burning fire or stove. You do this by multiplying the length, width and height.

Map the insulation of your home

Next, it is important to make an inventory of the extent to which your home is insulated. Do you have double-glazing throughout and wall and floor insulation? Then your home is classed as type A. Many modern homes or houses that have recently been completely renovated are well insulated. Is your home insulated, but not sufficiently? And do you not have double-glazing throughout? Then your home is classsed as type B. Is your home poorly insulated and you have no double-glazing? Then your home is classed as type C.

View the required capacity in the graph

Then read from the graph below the capacity required to heat your living space. The capacity of a fire or wood-burning stove is expressed in kilowatts (kW). When visiting the showroom, you can focus your search specifically on fires and stoves with this capacity. If you are still in doubt, for example about the insulation class of your home, you can of course also ask the dealer. It also makes a difference whether you live in a terraced house, where little heat is lost, or in a detached house.

Differences in output by wood type

Unlike a gas fire or gas heater, the fuel used also plays a role in the performance of a wood-burning fire or stove. Certain types of wood burn more easily or longer than others. Your heating behaviour also affects the efficiency.

There are several reasons why it is wise to choose suitable firewood. Painted wood, wood with glue residues and wet wood are the wrong fuels for a wood-burning fire or stove. These cause offensive odour and pollution for you and your environment. Heating with proper firewood, on the other hand, has a pleasant smell and gives you clean, efficient combustion.

More information about sensible heating and about the different wood types.

Capacity of pellet stoves

For pellet stoves, slightly different calculations apply. A pellet stove generates heat using a residual product from the wood industry. Many pellet stoves are fitted with a thermostat and an automatic mechanism to supply pellets. This makes it easier to regulate the heat output. A pellet stove can deliver more capacity in the middle of the winter than on a chilly evening in the spring or autumn.


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