Burn only dry wood – Newly cut wood needs to be adequately dried
The rising cost of electricity has increased interest in wood burning. HSY advises that only dry wood should be burned in the fireplace. Burning wood that is too moist produces a lot of emissions and is also inefficient in terms of energy.
Burning wet wood and waste produces emissions harmful to health
The use of fireplaces generates smoke, i.e. emissions into the air. The emissions from wood burning have a significant impact on people’s health, as they are generated in residential areas and released into the breathing air of the surrounding environment. According to the monitoring of the Helsinki Region Environmental Services Authority (HSY), wood burning produces, among other things, a large amount of fine particles and PAHs that increase the risk of cancer. However, everyone can influence how cleanly the wood burns.
The type of wood used is not very important in terms of emissions, but the moisture content of the wood is. Burning dry wood also has the advantage that it produces more heat than burning damp wood.
"The most important thing is to burn only dry wood, and no waste at all, in the firebox. Burning wet wood and waste generates a lot of emissions harmful to health into the air. These emissions can be many times higher than when burning only dry wood and otherwise using your fireplace correctly", says Nelli Kaski, Air Quality Expert at HSY.
Three tips for identifying dry wood
Some users of fireplaces acquire the firewood from their own forest. In this case, it is important to make sure that the firewood has been allowed to dry for a sufficiently long time. The water content of newly cut wood is about half. In good conditions, it can take just one spring and summer of air drying for wood to become dry enough for burning. However, air drying for two summers is often required, in which case it is referred to as last year’s wood.
Before burning, everyone can easily test whether the firewood is dry enough. There are three clear ways to do this: weight, cracking, and sound.
"Dry firewood weighs about half as much as damp wood. Hitting two pieces of dry wood together produces a clear, echoing sound, while the sound produced by damp wood is duller. Dry wood also cracks at the ends. Wet or still damp wood is solid", Kaski says.
A good woodshed is ventilated and protects the wood from rain
“It is important to store wood correctly so that the firewood dries and stays in good condition. The absolute best place to store firewood is a ventilated woodshed. It protects the wood from rain and keeps it dry”, Kaski says.
In a good woodshed, the air circulates through gaps in the floor, walls and ceiling. If the firewood is covered very tightly, moisture can condense and the wood can become mouldy. It is also not recommended to store wood indoors. Firewood should only be brought inside to warm up 1–2 days before burning.