WOOD BURNING APPLIANCES WOOD FUELS WOOD LINKS

This page will give you basic facts about wood burning appliances and wood fuel and will provide you with links
to other organisations that can supply more information.

WOOD BURNING APPLIANCES

Many solid fuel appliances are now multi-fuel and can burn both wood and coal. These include open fires, stoves, roomheaters, cookers and freestanding boilers. The manufacturers’ specification will tell you what you can burn; and especially important if the appliance has a boiler, the average output that you can expect by burning the different fuels.
Some appliances are manufactured solely for burning wood. They have a solid fuel bed with no bottom grate . However, some can be converted to burn solid mineral fuel by fitting a grate. A grate must be used when you are burning solid mineral fuels because these fuels burn hotter and produce more ash than wood fuel. The grate allows the ash to fall away from the fire bed and ensures that cool air is available underneath the fuel.

You will find information on a selection of manufacturers and importers of wood burning appliances in our links section. Wood burning grates and appliances can be purchased from many stove shops, fireplace showrooms, or selected builders’ merchants. They can also be obtained through heating engineers.

Purchasing on the internet or though a warehouse may be perfectly satisfactory so long as you understand the level of technical assistance and support is likely to be less than through the other routes. We would always recommend you consult a HETAS Engineer prior to purchasing an appliance. They will be able to advise whether the chimney you have is satisfactory and whether the proposed appliance is suitable for your heating requirements. Visit the HETAS website, www.hetas.co.uk for a list of HETAS Registered Engineers. Details of your nearest appliance showroom can be obtained by telephoning the Solid Fuel Association on 0845 601 4406 / 01773 835400.

Building Regulations
– Any installation of a heating appliance, or modification to a chimney such as relining, has to be carried out in accordance with Building Regulations (Part J and Part L in England and Wales and the Scottish Building Standards Agency Technical Handbook in Scotland). In England and Wales there is also a requirement that Building Control Consent is obtained for such work unless the work is carried out by a Competent Person. For solid fuel and wood burning appliances a Competent Person is someone who is registered with a scheme operator, such as HETAS established as such under Building Regulations Part J for that type of work. (For further details visit our general links page for HETAS and visit www.planningportal.gov.uk to view England and Wales Building Regulations and www.sbsa.gov.uk to view the Scottish Regulations). There are proposals to introduce similar requirements for competent persons under Scottish Building Regulations and there is a voluntary Scottish HETAS/SFA scheme for engineers operating at the moment. Visit The HETAS website to access the list of Scottish engineers.
Wood Pellet Stoves
Wood pellet stoves are very efficient. The pellets are either gravity fed or screw fed into the appliance as required and there is very little ash to dispose of. Most models incorporate sophisticated automation by microprocessor, enabling the temperature to be set and maintained by controlling the rate of feed of the pellets.

They will typically incorporate a remote control for electronic ignition and some have their own back-up power supply in the event of a mains power failure. The larger boiler models are designed for installation in kitchens or utility rooms and can be screw feed from silos outside the house. It is essential that the fuel is kept dry and the pellets must be of good quality (see section on wood fuel below). A selection of importers and retailers of wood pellet appliances will be found in the links section of this page.
Building Regulations -At the moment, the installation of wood pellet burning appliances has to comply with UK Building Regulations Part J (and SBSA Technical handbook in Scotland). This means they have to conform to the conventional flue arrangements as for other wood burning and coal burning appliances, even though the manufacturers may specify less stringent requirements in their installation instructions. Most of the appliances are imported and different Building Regulations apply in their country of origin. Future revisions to UK Building Regulations and the introduction of Harmonised European Standards may reflect the differences in the combustion process between these and conventional wood burners and different flue arrangements may become possible. (Check our news page for information).

Smoke Control Areas

If you wish to burn any type of wood fuel and you live in a smoke control area, you may only do so if you burn wood on an “exempt” appliance. An “exempt” appliance is one which is exempted to burn unauthorised fuels in smoke control areas, under Regulations published under the Clean Air Act.
Exempt Appliances
Certain appliances are presently exempted by DEFRA under the Clean Air Act. A list may be found here www.uksmokecontrolareas.co.uk).
 
top of page


WOOD FUELS
Logs (download 'Guide_to_Wood_and_Multifuel')
The most common form of wood fuel at the moment is logs. These will usually come from local sources and can be brought from a variety of outlets – e.g. coal merchants, farmers, tree surgeons. It is important the logs are dry and well seasoned. Burning wet or unseasoned wood is less efficient and can cause harmful build up of deposits in the chimney over a very short time. Thick coatings of creosote or resinous material can cause chimney fires, or prevent the chimney functioning properly. This can allow harmful fumes to escape into the dwelling.

Efficient burning is achieved by setting the appliance to burn fast after stoking. 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 should not be banked up with logs for overnight burning. A bright fire which has turned the wood into charcoal should be left with the day’s ash, no secondary air and minimal primary air.
If you buy logs which 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 3 to 4 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 The table below provides a useful comparison. 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.

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. The logs and wood 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 weights 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.

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.

    Weight per
m3 in kg
Gross heat value
kW/kg (btu/lb)
% Moisture
when green
Seasoning time
in summers
Hardwoods (fully air dried) Ash 674 4.1 (6,350) 35 1
  Beech 690 4.3 (6,700) 45 1-2
  Birch 662 4.1 (6,350) 45 1
  Elm 540 3.6 (5,600) 60 2-3
  Oak 770 4.5 (7,000) 50 2-3
  Poplar 465 2.6 (4,100) 65 1
Softwoods Pine/Fir 410 2.6 (4,100) 60 1

Wood Pellets
Wood pellets are used on specially designed stoves. Pellets are typically made from timber waste from sawmills. The wood goes through a fairly lengthy process of transformation before it is finally extruded as hard pellets. In spite of the processing, the fuel is still carbon neutral and so is less harmful to the environment than other fossil fuels. For commercial undertakings, as with any wood fuel, wood pellets do not attract climate change levy tax.

There are at present a limited number of pellet producing plants in the UK although there is some encouragement to produce from local sources. Some pellets are being imported in the meantime. The pellets for domestic roomheaters and boilers are being supplied in prepacked bags, usually 10kgs in weight, which makes them a handy size to store and load into the hopper. For the larger boiler models, pellets can be delivered in bulk, but an appropriate silo must be available, connected to the boiler. At the moment most of the pellets will be supplied by the stove shop that markets the boilers, but see our links page below for other suppliers.


It is critical to ensure the pellets for domestic stoves are of good quality. European standards are presently being drawn up but in the meantime be aware that pellets generally come in two sizes and the 6mm ones are most common for use in roomheaters/stoves. Good quality pellets will maintain their integrity through the handing process and be made from virgin wood. You should not use wood pellets made from reclaimed wood. It may contain harmful chemicals.

Wood Chips
Wood chips are generally a by-product of the arboriculture industry or created from waste timber. The fuel is used in screw-fed boilers that have the capacity to fuel local micro-chip systems and larger buildings such as leisure centre, where commercial sized boilers are needed. It is important to ensure stored wood chips do not contain excessive quantities of moisture.
 
Manufactured Wood Briquettes
These products are manufactured from sawdust and bound or pressed together into a log shape. Some incorporate an inflammable substance that makes the product easy to light. Some are authorised for use in smoke control areas.

Heat Logs (pictured right) are a by-product of the sawmill industry and consist of hardwood sawdust at 6% moisture content. This is compacted under high pressure and lignin from the wood itself binds the particles together, removing the need for further chemical additives.
Typical characteristics of wood briquettes:

  • Suitable for use on open fires.
  • Relatively expensive but will give a fire lasting for two or three hours.
  • Clean and handy to use and are ideal for a quick fire on a cold night.
  • Can be purchased from supermarkets, garages, other shops as well as from some coal merchants.

Wood and the Environment
Wood fuel described as being from a “sustainable” source is obtained from the thinning and management of woodland. This activity can be of benefit to the environment, creating more light and open spaces and potentially increasing biodiversity in the woodland.

Carbon Emissions
Wood fuel can be very near to being carbon neutral. It absorbs as much carbon dioxide in its growth as it releases when it is burnt. For this reason, the installation of wood fuel appliances is currently treated more favourably in the Building Regulations. Typical household carbon emissions when using different fuels are shown in the adjoining table.

Electricity 128 kg
Coal 116 kg
Oil 88 kg
Gas 67 kg
Coal/wood (50%) 58 kg
Wood Zero
top of page


WOOD LINKS

Manufacturers of Wood Burning Stoves

A J Wells (Roomheaters and Stoves, with and without boilers) www.charnwood.com Tel: 01983 537777
Dunsley (Stoves and Open Fires with and without boilers) www.dunsleyheat.co.uk Tel: 01484 682635
Aga Rayburn (Stoves and Cookers and Open Fires, with and without boilers) www.aga-web.co.uk Tel: 0845 3381365
Woodwarm (Stoves and Roomheater, with and without boilers) www.woodwarmstoves.co.uk Tel: 01884 35806
Percy Doughty & Co (Wood burning and multifuel stoves) www.percydoughty.com Tel: 01204 868 550

Wood Suppliers
Logs are generally available locally through coal merchants or other suppliers.
Big K Products UK Limited, Big K Products UK Limited, Whittington Hill, Stoke Ferry, Norfolk, PE33 9TE
National supplier of FSC certified wood such as seasoned hardwood logs, kiln-dried pizza logs, as well as eco-friendly heatlogs, wood fuel and firelogs, instant firelogs, and kindling to trade and enduser.
www.bigk.co.uk
Certainly Wood Ltd. (Now HETAS Approved Firewood Supplier) Lower Lulham, Madley, Hereford HR2 9JJ
Tel: 01981 251796
www.certainlywood.co.uk
D J Davies Fuels - FSC accredited for all wood fuel supplies.
Tel: 01269 850224
www.djdaviesfuels.co.uk
Logs2U, CPL Distribution Limited, Mill Lane, Wingerworth, Chesterfield S42 6NG
National supplier of logs, kindling and firewood.
www.logs2u.co.uk
PurePowerPellets (part of the Fergusson Group) -Suppliers of wood pellets across the UK.
Tel: 01786 477211 
www.purepowerpellets.co.uk
Rocfuel - Using the experience, expertise and logistics infrastructure of the Hargreaves Group we are able to promote the supply of premium quality wood pellets across the UK via our subsidiary company, Rocfuel.
Tel. 01977 664784.
www.hargreavesservices.co.uk/woodpellets.aspx

Specialist Installers
Engineers who are registered to install mechanically fed wood and wood pellet systems are
listed on the HETAS website www.hetas.co.uk and this speciality is shown on the list of services they provide.

Grants
A reduced rate of VAT at 5% is applied on the purchase and installation of wood boilers. The definition of a wood boiler is strictly limited and does not apply to any boiler that is available as a multifuel model. For further details of when the reduced rate is applicable visit www.soliftec.com

Other Organisations
For information on Smoke Control Areas, exempt appliances and fuels go to www.uksmokecontrolareas.co.uk.

HETAS The Quality Assured Fuel scheme members are listed here:
http://guide.hetas.co.uk/guide_quality_assured_fuel_directory.html

top of page
part of the Solid Fuel Association website