The wood must be thoroughly dried so that it can burn properly in the fireplace and heat optimally Photo: picture alliance/dpa/dpa-tmn
From BZ/dpa
Enjoy a warm home and still save energy costs – everyone who has a fireplace or tiled stove can do that. What to consider if you heat with firewood instead of oil or gas.
Freshly felled wood is damp and has a low calorific value. Because some of the energy is lost when excess water evaporates from the wood.
Conversely, this means that in order to be able to heat well with firewood, it must be dry. The Industry Association for House, Heating and Kitchen Technology (HKI) draws attention to this.
Split logs dry particularly well. They also provide enough surface area for the flames in the oven later on – and thus ensure optimal combustion. It is also best to store firewood in an airy place to dry.
It is even regulated by law how much wood has to dry before it can be burned: the residual moisture content must be less than 25 percent. This corresponds to less than 20 percent water content. For comparison: Freshly felled wood from the forest can contain up to 60 percent water content or 150 percent moisture content, depending on the season and type. Inexpensive measuring devices for checking are available at hardware stores.
It is also important that the firewood is untreated – i.e. free of varnish, paint, impregnation or coatings. Burning such substances is prohibited and may be hazardous to health.