ENVIRONMENTALLY FRIENDLY ENERGY

In general, any untreated wood can be used as firewood. However, there are differences in the energy content of different types of wood and in the way in which they burn. Softwoods and hardwoods have a very similar heating value, but their energy density or, in other words, their heating value per unit volume, is very different. Hardwoods have a much higher energy density than softwoods. This means that less space is needed to store hardwoods than softwoods with the same heating value. This difference is demonstrated even more clearly in the case of wood or lignite briquettes (from Heizprofi, for example) which are highly efficient energy sources. However, softwoods such as spruce and pine burn much faster and are therefore ideal for use as kindling. For a long-burning fire, beech or oak are the best choices. Ash produces the most attractive flames, while a birch fire has a pleasant scent. Poplar and willow are not particularly suitable for burning.

Moisture in the wood has a significant influence on its heating value. Firewood should therefore be properly dried in order to be energy-efficient. Firewood must be split and stored for at least two years in a sheltered, airy place to allow it to season, until the residual moisture content is less than 20 percent. Freshly cut wood can therefore usually be bought more cheaply. Damp wood burns inefficiently and produces a lot of smoke. It can cause soot and tar to form in the chimney which can result in chimney fires. Pellets have a moisture content of less than 10 per cent, and this level of moisture must not be exceeded. As a result, their heating value is around 5 kilowatts per kilo, which is equivalent to about half a litre of heating oil. Lignite briquettes from Heizprofi have a heating value of around 5.5 kilowatts per kilo. They have a consistently high quality and, unlike logs, do not need to be split or seasoned. They need a lot of initial heat to ignite them and then provide steady, long-lasting warmth.