Wood-fuelled heating
Wood-fuelled heating systems, also called biomass systems, burn wood pellets, chips or logs to to provide warmth in a single room or to power central heating and hot water boilers.
- A stove burns logs or pellets to heat a single room - and may be fitted with a back boiler to provide water heating as well.
- A boiler burns logs, pellets or chips, and is connected to a central heating and hot water system. A wood-fuelled boiler could save you nearly £600 a year compared to electric heating.
The benefits of wood-fuelled heating
- Affordable heating fuel: although the price of wood fuel varies considerably, it is often cheaper than other heating options.
- Financial support: wood fuel boiler systems could benefit from the Renewable Heat Premium Payment and the Renewable Heat Incentive.
- A low-carbon option: the carbon dioxide emitted when wood is burned is the same amount that was absorbed over the months and years that the plant was growing. The process is sustainable as long as new plants continue to grow in place of those used for fuel. There are some carbon emissions caused by the cultivation, manufacture and transportation of the fuel, but as long as the fuel is sourced locally, these are much lower than the emissions from fossil fuels.
Costs, savings and earnings
Costs
A pellet stove will cost around £4,300 including installation. Installing a new log stove will usually cost less than half this, including a new flue or chimney lining.
For boilers, an automatically fed pellet boiler for an average home costs around £11,500 including installation, flue, fuel store and VAT at 5%. Manually fed log boiler systems can be slightly cheaper.
Pellet costs depend mainly on the size and method of delivery. Buying a few bags at a time makes them expensive. If you have room for a large fuel store that will accept several tonnes of pellets at a time, delivered in bulk by tanker, you can keep the cost down to around £190 per tonne in most parts of the UK.
Logs can be cheaper than pellets, but costs depend on the wood suppliers in your local area, as they cost a lot to transport. If you have room to store more than a year’s worth of logs you can save money by buying unseasoned logs and letting them season for a year. Search for wood fuel suppliers in your area at the Log Pile website.
Savings
Savings in carbon dioxide emissions are very significant - around 7.5 tonnes a year when a wood-fuelled boiler replaces a solid (coal) fired system or electric storage heating. Financial savings are more variable - if you replace a gas heating system with a wood-burning system you might save £100 a year, but if you are replacing electric heating you could save as much as £580 per year.
This table shows how much you could save by installing pellet central heating in a typical three-bedroom semi-detached house with basic insulation:
| Fuel replaced | Expected saving | Expected carbon dioxide saving |
| Electricity | £580 a year | 7.5 tonnes a year |
| Oil | £280 a year | 4 tonnes a year |
| LPG | £720 a year | 3.5 tonnes a year |
| Coal | £300 a year | 7.5 tonnes a year |
| Gas | £100 a year | 3 tonnes a year |
These savings assume the house has been insulated, as we always recommend that people insulate their homes properly before considering installing renewable energy systems. So you could save money from insulating, and then save the money from switching to wood heating too!
Earnings
You may be able to receive payments for the heat you produce from a wood boiler through the government’s Renewable Heat Incentive (RHI). This scheme should be launched in October 2012.
From August 2011, you may be able to get help with the installation costs of a wood boiler through the Renewable Heat Premium Payment scheme.
Pellet and log stoves are not eligible for Renewable Heat Premium Payments, and are not expected to be supported by the RHI.
Choosing a wood-fuelled heating system
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Boiler or stove?
Boilers can be used in place of a standard gas or oil boiler to heat radiators for a whole house, and to heat the hot water. Stoves are used to heat a single room, usually in conjunction with other heating systems, but may also have a back boiler to provide hot water. -
Chips, pellets or logs?
Chips are not suitable for heating a single house, but can be used to heat larger buildings or groups of houses. Pellets are much easier to use and much more controllable than logs; pellet boilers can run automatically in much the same way that gas or oil boilers operate. Log-burning stoves and boilers have to be filled with wood by hand; most pellet and chip burners use automatic fuel feeders which refill them at regular intervals. Logs require considerably more work, and you will need a lot of logs to heat a whole house, but they can be cheaper than pellets if you have a good local supply. -
Do you have a local fuel supplier?
Some companies now offer deliveries of pellets anywhere in mainland Britain and Northern Ireland; supply of logs is much more variable. -
Do you have space?
Wood boilers are larger than gas or oil equivalents. You will also need space to store the fuel: somewhere that's handy for deliveries but also appropriate for feeding the boiler. -
Do you have somewhere to put the flue?
You will need a flue which meets the regulations for wood-burning appliances: a new insulated stainless steel flue pipe or an existing chimney - though chimneys normally need lining to make them safe and legal. -
Do you need permission?
You may not need planning permission, but you should always check. All new wood heating systems have to comply with building regulations, and the best way to ensure this is to use an installer who is a member of a competent person scheme. -
Do you have a thatched roof?
Read HETAS's advice about building regulations (PDF, 741K).
