Pellets are standardised cylindrical pellets made entirely from natural wood residues such as planing shavings and sawdust. The dry wood residues are ground up and compressed into wood pellets under high pressure in special presses. Binders or additives are neither necessary nor permitted. The production of wood pellets from dry planing shavings requires approximately 1% of the energy contained in the fuel, whilst the use of damp sawdust requires approximately 5%. ‘Liquid wood’ thus has the best energy balance of all fuels.
If you use wood pellets for your heating system, you can use the following comparisons as a guide. Two kilograms of wood pellets are comparable in calorific value to one litre of heating oil. You need one cubic metre of space for 650 kg of wood pellets. This means that three cubic metres of wood pellets for your pellet heating system are roughly equivalent to 1,000 litres of heating oil. Wood pellets: liquid wood that is space-efficient and environmentally friendly to use.
The quality of the pellets plays a vital role in ensuring your heating system operates at its best. When purchasing pellets, please ensure that they comply with the quality standards set out in EN ISO 17225-2 A1. You can achieve the highest possible operational reliability by purchasing pellets from manufacturers who hold EN Plus certification (or DIN-Plus, ÖNORM M7135 or UZ38), as certification requires ongoing internal quality control. Before placing an order, inform your pellet supplier of these quality requirements and ask for confirmation upon delivery.
Some visual indicators of good pellet quality include a shiny, smooth surface, uniform pellet size and minimal dust. You can quickly and easily test the quality yourself by dropping some wood pellets into a glass of water. Good-quality pellets will sink immediately.
Diameter: 6 ± 1 mm
Length: 3.15 to 40 mm
Bulk density: > 650 kg/m³
Calorific value: > 4.6 kWh/kg
Ash content: < 0.7%
Fine material content: < 1%
As they grow, trees absorb CO₂ from the air. When wood is burned, exactly the same amount of CO₂ is released, so the emissions are no higher than they would be if the wood were to decompose naturally in the forest. Heating with wood pellets is therefore carbon-neutral and makes an important contribution to climate protection.
The quality guidelines for transport and storage logistics are set out in ENplus and ÖNORM M7136.
Pellets are supplied by fuel retailers in the following forms:
- for manual filling of storage bins in 10, 15 and 30 kg bags, as well as in big bags of approx. 1 tonne on Euro pallets
- for automatic room-by-room delivery in bulk using silo pump trucks, quantity as required (quoted and delivered in kg)
Pellets must be transported and stored in a completely dry condition. If stored in damp conditions, they swell considerably. The pellets must therefore be protected from moisture throughout the entire process, from transport and storage right through to combustion.
