Wood is the most commonly used fuel on open fires or stoves and rightly so. Burning wood does release carbon dioxide into the atmosphere, however the amount of carbon dioxide released is approximately the same as the amount absorbed by the tree during growth. Therefore, wood is widely accepted as a carbon neutral fuel. Wood fuel is available in many forms: logs, pellets, woodchips, heat logs and wood briquettes. With conventional energy prices increasing wood has become an even more attractive fuel for heating. Wood can be divided into two major classes, hardwood and softwood. Measured by weight, hardwoods and softwoods have similar energy contents (around 20MJ/kg dry) however Hardwoods are typically twice as dense as softwoods as they are slower growing, so you would require less hardwood to produce the same heat output as softwood. The most important factor when using wood as a fuel is that it has a low moisture content (MC). Freshly harvested wood can contain as much as 80% depending on the species and the time of year it was felled. As the wood moisture level increases, its useful energy content decreases. At 60% MC wood can have an energy content of 6MJ/kg but at 25% MC this can increase to 14MJ/kG. Burning wet wood produces excess steam and excess smoke which is a sign of incomplete combustion, this increases the build up of tars in the chimney which enhances the risk of chimney fires and reduces the efficiency of the chimney. To obtain maximum efficiency from your stove using the minimum amount of fuel only burn wood with a moisture content of 20% or less. The use of a moisture meter is the best way to monitor this. (quick find no.SMO2535). Removing the water from the wood is known as seasoning. This term suggests a period of time, and for natural air drying up to two to three years is recommended. We offer a selection of log stores for this purpose, please contact us for details. Firebox Stoves does NOT recommend the use of pallet's or any treated / painted wood. The use of wood composites for example Plywood, chipboard, MDF etc. should be avoided and could prove VERY DANGEROUS.