Firewood and moisture


Freshly beaten wood smokes when burned and has only a low calorific value. With increasing drying, this value increases. Firewood must therefore be sufficiently stored. Heating with dry wood relieves the environment and saves costs.

Firewood with residual moisture does not belong in the oven

When burning wet or damp wood, the water contained in the wood must first evaporate. Only then can combustion begin in the furnace. It comes to heat loss. In the temperature dropped by the steam not all components of the wood burn. Uncombusted wood gases enter the chimney and settle in the chimney as tar. The deposits can lead to a chimney fire. High wood moisture in firewood is uneconomical and harmful to the environment.

Disadvantages of freshly beaten, still damp wood

  • bad burning
  • heavy smoke
  • lower heating power
  • Soot of fireplace and chimney
  • Ecological damage

Pollutants due to damp firewood

If the firewood is damp, high amounts of pollutants are released when burning. At a humidity of 25 percent, the pollutant load triples. This becomes visible through dark clouds of smoke and unpleasant odor far in the neighborhood. The amount of fine dust in the ambient air increases. The toxins also enter the house and pollute the respiratory tract of the inhabitants.

Pests in damp firewood

Firewood with high residual moisture that is stored in poorly ventilated areas can be attacked by the weevil. The cockroach prefers a high humidity environment. If it is discovered on the wood supply, it must be destroyed for safety's sake. Otherwise there is the danger that the beetle will also change to other woods. In the house built wood or furniture can be infested.

Measure moisture

With a wood moisture meter you can check the moisture content of the firewood. If the wood has already been delivered with too high humidity, you can complain to the supplier. If you store fresh wood for drying, the meter gives you information about the wood moisture content of your wood supply at regular intervals. Only heat the wood when the correct drying level has been reached. Only then do you heat energy-consciously and with low emissions.

How to properly heat with wood

With a wood moisture content of 15 percent, you achieve the best calorific value and release the lowest amount of pollutants. In most cases, measured values ​​of 16 to 20 percent are measured in oven-ready wood. This puts the firewood in an average and tolerable range. If you notice a humidity of more than 20 percent when measuring, give the wood some more time to store and dry. In the next heating season, it has reached the ideal value. For fresh firewood, always assume a two-year storage period.

Tips & Tricks

The different types of wood require different periods of drying before they can be used as firewood. Poplar and spruce are sufficiently dried after one year. Linden, birch and alder are dry after one and a half years and beech, ash and fruit trees take two years.

Artikelbild: NatureDiver / Shutterstock


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