The Importance of Dry Firewood: For a Warm and Optimal Fire
Why is dry firewood important? Read more about firewood requirements and why drought is a critical factor.
Why does firewood have to be dry?
If you want to enjoy a cozy wood fire in your home, it is important to use well-dried firewood. One of the most important requirements is that the wood is completely dry. There are many types of wood to choose from, but not all are suitable for use in your stove or fireplace. To make things clear, we have listed some criteria that your firewood must meet:
- The wood must be dry, with a moisture content between 12% and 18%.
- Compressed wood, such as briquettes, is also a good option.
- Split wood from deciduous trees such as alder, birch, ash, and beech is suitable. Oak is less suitable because it does not reach a high combustion temperature.
Why is dry firewood so important?
Dry wood is essential to get the stove to the right temperature. If the wood is too moist, the temperature will remain too low and the fire will not burn optimally. This can lead to a foggy window and deposits (creosote) in your chimney. A buildup of creosote significantly increases the risk of a chimney fire. Creosote is a flammable, tar-like substance formed from soot deposits. Unburned particles stick to the walls of the chimney. Using dry wood and maintaining higher temperatures can help prevent creosote buildup.
Read more about maintaining the right temperature in your woodstove.
How can you dry firewood?
Of course, you can opt for kiln-dried firewood, which is dried in kilns to reduce the moisture content. In most cases, kiln-dried firewood contains less than 20% moisture. It is also possible to dry fresh firewood yourself. The best place to do this is in an outdoor wood shed, where the wood is exposed to sufficient wind to dry. Be careful not to expose the wood to continuous rain, as this will significantly increase the drying time before the firewood is sufficiently dry.
Wet wood in the fireplace: how do you determine the optimal moisture content of firewood?
Wet wood in the fireplace is uneconomical and harmful to the environment and your stove. But when is wood actually considered wet? How dry is dry enough? This article explains what the moisture content of firewood can be, what the consequences are of too wet wood in the fireplace and how to store logs correctly .
Why too wet wood in the fireplace is problematic
You would think it would take a little longer to burn wet wood. But in fact a whole series of other, detrimental processes are set in motion in the background.
First of all, it is important to know: Less combustion actually takes place in the fireplace than with so-called wood gasification. Embedded in the wood are small chambers filled with gas. When you light a fire in the oven, these gases burn.
During the combustion process, the water in the wood is also heated. However, this removes the energy from combustion. Overall, significantly lower temperatures are achieved. Conversely, this means: the lower the combustion temperature, the less heat energy the furnace can emit. And the wetter the wood is, the more noticeable this effect is.
Wet wood in the fireplace can have numerous negative consequences:
- With every percent increase in wood moisture, pollutant emissions increase disproportionately.
- Lower temperatures during the combustion process mean it is less efficient. You get less heating power than would be possible with drier wood.
- When burned, dark smoke and a sharp odor are produced. If it is a boiler or a Swedish stove, these can even enter the room.
- The dark smoke causes soot to settle on the glass of the fireplace, on the stove and in the chimney.
Firewood moisture: When is wood suitable for burning in the oven?
The moisture content of firewood can be classified into different levels:
- Ideal wood moisture: Wood with a residual moisture content of approximately 15 percent is most suitable for the fireplace and has the optimal heating value. In this condition, combustion is optimal and effective, leaves as little residue as possible and is friendly to the environment. Even lower values are possible. However, it is not easily possible to further reduce the residual moisture to below 11 percent. The wood would retain moisture from the surrounding air.
- Slightly increased moisture: Firewood often measures a moisture content between 16 and 20 percent. In this area combustion is not particularly efficient, but still acceptable.
- Increased firewood moisture: If the residual moisture of the firewood is between 21 and 24 percent, you should not use it yet. Better keep it for another year to lower the humidity.
- Moisture above 25 percent: If the moisture content of firewood is 25 percent, it is not legally allowed to be used as firewood. Wet wood in the fireplace produces a lot of smoke, which is harmful to the environment.
Tip : Do you want to measure the moisture content of your firewood? For this you need a wood moisture meter. This measuring device conducts electric current via two electrodes pressed into the wood. Based on the measured resistance, conclusions can be drawn about the water content in the firewood.
Avoid wet wood in the fireplace: store logs correctly
The following points summarize at a glance everything you need to remember to store firewood correctly:
Good storage of firewood
First make sure the logs are the right size. Pieces with a diameter larger than 5 centimeters must be split at least once. A length of 30 centimeters is perfect because this corresponds to the length of most fireplaces. Make sure you get logs of different thicknesses, from thin kindling to thicker logs.
To dry slowly and gently, the wood shed needs good air circulation and, ideally, regular exposure to sunlight.
The optimal storage location for firewood
It is best to store your firewood under a shelter on the south or west side of your house or under a self-made corrugated iron roof. Here it is protected from rain and snow. Storage in the basement or a closed shed makes less sense because the air does not circulate and the escaping moisture is not removed. In the worst case, the wood starts to mold.
Choose a surface that allows air circulation, such as a pallet or stones. The wood should not lie directly on the floor. If you simply stack the wood, it will dry faster than in stacks due to good air circulation. But since it takes up quite a bit of space, you can stack it after the first drying phase.
The storage period for firewood
A freshly cut tree has a wood moisture content of approximately 50 to 60 percent. It takes at least a year before it has the right residual moisture to use as firewood. This is especially the case with quick-drying species such as spruce, pine or birch. For slower drying firewood from ash, oak, beech or fruit trees, you should allow the wood two years to reach the optimal calorific value.
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