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Why dry wood


Why have dry wood for heating?

Wood burning is a chemical process, which causes heat production. Each type of wood has a slightly different chemical composition and different humidity, that
 is why it burns differently, and has different calorific value.

Wood humidity

Wood moisture has a major impact on its calorific value. Therefore the wood, which you will use for your fireplace or stove, must be dried up properly.

Moist wood has considerably lower calorific value, because most heat is used for the evaporation of water (directly under the bark and bast, wood may contain as much as 75 % of water).

Moist wood releases a lot of smoke and tar, and also produces a few flames. Thus it causes clogging of the furnace, contamination of heat resistant glass, and clogging of the chimney.

  • 1 kg moist wood (40 % humidity) produces 8,370 - 10,467 kJ/hour.
  • 1 kg dry wood (20 % humidity) produces 14,650 – 16,750 kJ/hour.
  • An ideal wood humidity for burning in fireplaces and stoves is up to 20 %.
  • On average, fresh wood has 50% humidity, humidity of wood dried in forest is 25-30%, and humidity of dried up wood (dried in the open air) is 10-20%. 

‌General principles

  • ‌Suitable wood for heating should be ideally dry.
  • For quicker drying, big chunks should be chopped into small logs.
  • Wood should be stored in a sheltered, aired place, protected from rain.

 Although the woodshed does not chop wood for you, it will help you a lot with other things.


Our customer reference:

We were extremely surprised by the quickness of drying, which exactly fits in today’s hasty times.  We store wood in March  –  April, and the wood is        10–15 % dry for the upcoming heating season, which is reasonable. Petr Skokan, Meziříčí


KLUH s.r.o.
Obránců míru 278
542 01 Žacléř

Czech Republic


+420 608 411 927




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