Wood Fuels

There has been a great resurrgence in log burning as many people have had 'multifuel' stoves fitted, and most Approved Coal Merchants can now supply good quality logs and have the knowlege to be able to give their customers sound advise on how to burn firewood safely and efficiently.

Wood can be divided into two main categories ......... 'Hardwood' from deciduous trees and 'Softwood' from coniferous trees.

Hardwood logs are a lot denser than softwood logs, and give a much higher heat output ........ the heat content of softwood is almost half that of hardwood by volume, so you need twice as many softwood logs to produce the same amount of heat as hardwood logs.

However, softwood does light easier and burns quicker due to the resin content. This results in more immediate heat so softwood is ideal for kindling and starting a fire.

Burning inadequately seasoned woodfuel with high moisture content will damage flueways and could lead to blocked flues and chimney fires.

The moisture content of various types of wood varies enormously, especially if the trees have been felled in the summer time when up to 65% of the weight of the timber can be water. Ideally trees should be felled during the winter when the moisture content is at it's lowest.

Wood should be properly 'dried' or 'seasoned' (for between 1 - 2 years) before being burnt and the target moisture content for this is 20% or less, and certainly not over 25%.

Logs that have been properly seasoned will have bark which comes away easily, will split across the grain and will create a hollow ringing sound when 2 logs are knocked together.

Wood which has been 'kiln dried' offers the lowest moisture content and will perform far better when burnt than naturally seasoned wood - 4 kiln dried logs produce the same heat output as 6 seasoned logs or 12 unseasoned logs.

The Approved Woodfuel Merchant Scheme was launched in July 2012 and lays down a basic standard of service for wood fuel retailers. Customers buying firewood from a Scheme member can be confident that the firewood is correctly described (kiln dried, seasoned hardwood, seasoned softwood or unseasoned) and that the Scheme member will be able to provide advise on the safe and efficient use of wood burning appliances and offer an appropriate level of customer service.

It is important to note that under the Clean Air Act, it is an offense to use wood as a fuel within a 'Smokeless Zone' unless it is burnt on an approved DEFRA exempted appliance.