Most commonly firewood is burned in wood burning stoves or on open fires. Many wood burning stoves are what is called ‘multi-fuel’ which means you can burn both firewood and coal derived solid fuel. While your stove may be able to burn coal it is far more ecologically sustainable to burn firewood. If you are interested in buying a wood burning stove we would highly recommend the good people at stovesonline.co.uk
Firewood logs are currently the most common form of wood fuel. They will usually come from local sources and can be bought from a variety of outlets – e.g. garden centers, farmers, tree surgeons etc. It is important the logs are dry and well seasoned with a moisture content in the low 20s or below. Burning wet or unseasoned wood is less efficient and can cause harmful build up of deposits in the chimney over a short time, the reason is that when the logs heat up the sap and resin within the logs will be boiled out first causing thick coatings of creosote or resinous materials which can cause chimney fires, or prevent the chimney functioning properly. This can also allow harmful fumes to escape into the home and indeed the environment.
Efficient burning is achieved by setting the appliance to fast air flow. This will ensure that all the gases are fully burned. Only set to slow burn when all wood has been reduced to charcoal and ash. Newly added wood set to burn slowly creates smoke and creosote in the chimney. The stove or open fire should not be banked up with logs for overnight burning.
If you burn wood, you should have your chimney swept at least twice a year. Do not burn any painted or treated wood. Treated or painted wood will emit chemicals which are potentially damaging to health and the environment. This also applies to MDF and chipboard.
By far the easiest way to find out is to use a firewood moisture meter – usually available for £20- £40. This is a small hand held device that will give you a percentage reading of the moisture in your wood – more details in the following FAQ. If you use your wood burning stove a lot then we would highly recommend purchasing a moisture meter. It can save you from purchasing hundreds of pounds worth of unseasoned wood! It can also save you money. If your wood delivery is acceptable but not perfect then you can negociate for a discount based on your moisture reading.
The only other way to judge the moisture content is by handling the wood to get a feel for it by sight, feel and weight. It is obvious to say but your delivery should look and feel dry! If it is clearly damp then it is likely the wood is left in the open. If so it wont matter how long it has been left to season. A bit of residual moisture on the service may have come from rain during the delivery but this should not affect the logs beneath, so it’s worth digging around to check. Finally, unseasoned wood is normally a fair bit heavier than seasoned wood. This comparison can be difficult to judge. The best advice here is to keep back a log of well seasoned wood, from previous deliveries, to use as a comparison.
Seasoned firewood should be under 25% moisture at the minimum – anything over this will struggle to burn. A moisture meter has a cap covering two metal prongs. You simply remove this cap, switch on the device and push the two prongs into your wood to get a reading. To get a good reading you need to split the log and test on the inside. We suggest you do this at the point of delivery as you are within your rights to refuse the load if your moisture readings are too high. A lot more info on this topic can be found here >>
If you buy logs that have not been seasoned, you should store them under cover but open to allow free air circulation for at least a year. Some logs may take 2 to 3 years to fully season. Bring the fuel into the house a few days before you want to use it to get it as dry as possible. Wood from different trees has different heat values . Wood fuel has typically less than half the calorific value of coal and smokeless fuel, so you must be prepared to use a greater volume of wood to heat your home or room, unless you use both wood and mineral solid fuel.
It’s ultimately buyer beware when purchasing logs – some things to be aware of: Under the Weights and Measures Act, coal and smokeless fuel have to be sold in defined weights, which makes it easy for you to compare the cost between suppliers. Unless there is a local statutory instrument in force, there will be no such statutory weight for deliveries of wood. Logs and firewood are usually sold in “nets” or by lorry load, so take care to check the amount you can expect to get for your money. Fresh felled wood weighs about one tonne per solid cubic metre but will lose up to half its weight when it becomes fully air dried, so find out for how long the wood has been seasoned before delivery.
Wood fuel is carbon neutral in other words trees absorbs as much carbon dioxide in its growth as it releases when it is burnt or if allowed to decompose naturally on the ground. For this reason, the installation of wood fuel appliances, such as a wood burning stove, are treated more favourably in Building Regulations.