If the wood is damp, most of the energy that it contains is used to evaporate this moisture. This means that very little energy remains for heating. Moreover, damp wood will lead to incomplete and therefore inefficient combustion, which will cause pollution, clog up the appliance and flue (with bitumen and tar) and damage your stove.
Specified fuel is dry chopped log firewood, Ø 8O – 150mm, at least two years old, moisture 12% to and log length 330 - 1,000 mm as per boiler type.
You can ensure maximum output and a long service life if you burn wood which has been left for at least 2 years to dry. The energy content declines dramatically with increased water contents.
Wood with 20% moisture contents has thermal power of 4 kWh /1 kg of wood.
Wood with 60% moisture contents has thermal power of 1.5 kWh /1 kg of wood.
Raw wood does not burn easily, produces a lot of smoke and substantially decreases the service life of your boiler and chimney. Boiler output drops as low as 50% and fuel consumption doubles.