How to make the most out of your firewood
A wood burning stove’s efficiency is defined by how much heat you get out of your firewood. Naturally, you want maximum efficiency from the firewood that you have spent time and money on. The most important factors for a high efficiency are…
- lighting a fire using dry firewood
- lighting a fire in a wood burning stove whose design, structure and technique have been developed to make the most out of your firewood
- lighting a fire correctly
Optimise the use of your wood burning stove
– use dry firewood
If you light a fire using firewood that has a moisture content above 18 %, the efficiency of the firewood will decrease drastically. This happens due to an incomplete combustion of the wood’s gases and heat loss in the chimney. Wet firewood simply reduces the efficiency. The reason why is that if firewood is wet much of the heat will be used to boil off the water content of the firewood. This means the heat will be so weak that you won’t make the most out of your firewood or of your wood burning stove.
When you light a fire using wet firewood…
- you won’t reach the optimal temperature and combustion in your wood burning stove
- the gases in the firewood won’t be burnt
- the heat you will get out of your firewood will be minimal
- the energy will disappear up the chimney as smoke
- you’ll pollute the environment
By lighting a fire using dry firewood and by correctly lighting the fire and having the right combustion, you will reduce the heat loss as much as possible.
Here you can read more about tests which show what happens when you light a fire using wet firewood.
Did you know…
One kilogram of dry firewood (moisture content below 18 %) contains 5.32 kWh of energy no matter the type of wood. (The only exceptions are birch bark and twigs which give off 20 % more. (Source: Lars Mytting’s book Solid Wood)
In practice, 1 kilogram of firewood will give off less, corresponding to 3.5 kWh per kilogram of firewood. The loss happens because of the moisture content and because the wood burning stove is not capable of using the firewood completely.
It’ll often pay off to buy a new wood burning stove
The difference between the heat that you’ll get out of an old and a new wood burning stove is big. Old wood burning stoves usually have an efficiency of about 40-60 % while a new wood burning stove has an efficiency of about 75-80 %. An open fireplace can have as little as a 10-15 % efficiency. (Source: Lars Mytting’s book Solid Wood)
A modern wood burning stove will release half as many particles as an old wood burning stove – thanks to the producers’ product development. Tests from the Danish Technological Institute show that for the past 10-12 years the particle emissions have been reduced by 60 %. Furthermore, the amount of firewood that a modern wood burning stove uses is 40-50 % less than the amount an old wood burning stove uses.
When you buy a modern wood burning stove with an automatic control device that regulates the air supply, there is a good chance that you’re making the most out of your wood burning stove. And you’ll use less firewood this way.
The difference between the optimal and the non-optimal use of you wood burning stove can amount to a difference of 25-40 % in the use of firewood.