The right fuels

Kindling wood

Kindling wood is dry, natural wood, finely split into thin splints, containing no or as little as possible bark. It is available from dealers ready for the fireplace, cleanly packaged into raschel bags or foil— usually about 200 mm long.

Wood is the classic fuel for any fireplace. It quickly heats the fireplace, burns rapidly and provides a romantic play of flames. Therefore, wood is the optimal fuel where the fireplace is to be used only for a short time. As a rule, only untreated, natural and dry wood must be used as firewood. Hardwoods such as beech or oak, but also birch and fruit-tree wood are especially suitable.

Due to the moisture it contains, freshly felled timber must not be burnt directly because moist wood not only burns less well but also emits pollutants due to its low combustion temperature. Only sufficiently seasoned firewood has the moisture content of 20 per cent required by the 1st BImSchV. This corresponds to a water content of 25 per cent. To achieve this, wood must at any rate be dried for one or two years, depending on the storage place conditions and its kind of processing (sawn or split).

To burn wood, the optimal water content is 15 to 20 per cent. A wood moisture meter helps you check the water content. Firewood should be free from soil, moss, mould spores and other contamination. Ensure this already when you buy the wood and check your fuel storage. Only use firewood of a length suitable for your combustion chamber. On pre-packaged containers (raschel bags, cartons), the filling quantity of the firewood must be exactly specified by weight or volume. Approximate declarations are inadmissible. Certification systems such as FSC or PEFC give you more certainty that purchased firewood stems from sustainable forestry.

Comparison of different measuring units for (bulk) firewood

Source: Excerpt from "Technologie- und Förderzentrum, Straubing, Umrechnungsfaktoren bestimmter Raummaße für Scheitholz" [technology and support centre, Straubing, conversion factors for certain cubic measures for firewood]

Wood is the classic fuel for any fireplace. It quickly heats the fireplace, burns rapidly and provides a romantic play of flames. Therefore, wood is the optimal fuel where the fireplace is to be used only for a short time. As a rule, only untreated, natural and dry wood must be used as firewood. Hardwoods such as beech or oak, but also birch and fruit-tree wood are especially suitable.
Due to the moisture it contains, freshly felled timber must not be burnt directly because moist wood not only burns less well but also emits pollutants due to its low combustion temperature. Only sufficiently seasoned firewood has the moisture content of 20 per cent required by the 1st BImSchV. This corresponds to a water content of 25 per cent. To achieve this, wood must at any rate be dried for one or two years, depending on the storage place conditions and its kind of processing (sawn or split).
To burn wood, the optimal water content is 15 to 20 per cent. A wood moisture meter helps you check the water content. Firewood should be free from soil, moss, mould spores and other contamination. Ensure this already when you buy the wood and check your fuel storage. Only use firewood of a length suitable for your combustion chamber. On pre-packaged containers (raschel bags, cartons), the filling quantity of the firewood must be exactly specified by weight or volume. Approximate declarations are inadmissible. Certification systems such as FSC or PEFC give you more certainty that purchased firewood stems from sustainable forestry.

Lignite briquettes

Lignite briquettes are pressed from dried, prepared lignite without the use of binding agents. In contrast to firewood, the factory-made fuel is characterised by its high degree of homogeneity and has a constant quality which is continuously checked by laboratories. Only low-emission lignite types of a particularly high quality are used to produce lignite briquettes.

The handy energy packs feature a substantially longer burning life compared to wood fuels and a very high calorific value. They release heat evenly and in a well controllable manner. Due to their high energy density, there is no need to constantly put on more lignite briquettes and embers last for many hours.

Lignite briquettes require more heat to start burning than wood does and it's best to ignite them on an existing fire bed. The combustion air flows around the briquettes from below through the grate at the bottom of the combustion chamber. They may be used in all closed fireplaces that have a grate and an ash pan. Their use requires examination and release by the manufacturer.

Wood briquettes

Wood briquettes are made from untreated wood shavings, wood planing chips and sawdust. High pressure is applied to produce them and sometimes starch (stearin, molasses etc.) is added as a binding agent. Depending on the kind of production and the raw materials used, the quality of wood briquettes may vary widely.

In Germany, only wood briquettes meeting the German standard DIN 51731 or the European standard EN 14961-3 may be used as fuel. Consider this when you buy wood briquettes and ask your dealer to certify compliance. The exact filling quantity must be specified on the package by weight or volume. Certification systems such as FSC or PEFC give you more certainty that the raw material stems from sustainable forestry.

Wood briquettes are characterised by a calorific value which is higher than that of firewood and they burn relatively rapidly. It's best to ignite them on an existing fire bed. Caution: Many wood briquettes expand while they are burning and this may damage the combustion chamber. Therefore, be sure to observe the operating instructions provided by your appliance manufacturer. To avoid dust and abrasion, transport wood briquettes carefully and store them in a dry place.

Wood pellets

Wood pellets are cylindrical sticks made of dried, natural wood waste (sawdust, wood shavings, and forest residues). High pressure is applied to produce them and sometimes starch (stearin, molasses etc.) is added as a binding agent. They are between 10 and 30 mm long, with a diameter of 6 to 8 mm. Wood pellets may exclusively be used in approved, electrical pellet-burning appliances.

The quality requirements for the standardised fuel are defined in the European standard EN 14961- 2. The values of the European standard are implemented by the new ENplus certification. When buying, look for the appropriate marking and ask your dealer for proof.

Wood pellets have a higher calorific value than firewood and burn with a short flame. Pellets are mostly sold in 15 kg sacks, or in large units for central heating systems. Specialist fuel dealers may also pump them into a storage room, pellet silo or pellet tank directly from a tanker. Caution is required when transporting and storing pellet sacks. The sacks must be transported cautiously to avoid dust and abrasion and should be stored in a dry place.

Hard coal

Hard coal is available in various grades and types. As a rule, only low-sulphur (< 1%) products with a low ash content should be used as domestic fuel. Depending on the grain size, domestic coal is offered as pea coal (5 to 25 mm), nut coal (25 to 90 mm) or cobbles (70 to 200 mm). The calorific value varies between 22 and 32 MJ/kg (anthracite), depending on type. In addition, hard coal briquettes (Extrazit, Ancit) and hard coal coke are also available from specialised retailers.

Important: Hard coal products must be used exclusively in heating appliances especially tested and approved for the purpose. Due to the very high ignition point, a very great starting heat is required to ensure clean burning of the fuel. As it contains little volatile matter, hard coal burns with a very short flame and is characterised by a very long burning time.

Be sure to observe the information and operating instructions provided by your appliance manufacturer. Unsuitable fuel or overfilling may seriously damage your heating appliance. Poor hard coal quality and incorrect operation may cause slag formation, high emissions and increased maintenance expenditure.