Judith's pellet boiler

Case Study

Judith has installed a wood pellet boiler. This is a compact appliance allows her to heat her 5 bedroom house using sustainable wood biomass fuel without having to worry about lighting fires.

Added: April 29, 2010

Watch video in youtube (length: 4:26)

Judith Thornton heats her 5-bedroom house using a wood pellet boiler connected to her central heating. Heating with wood pellets – made from compacted sawdust – is a very comfortable way of using wood biomass as a fuel. Judith’s pellet boiler keeps the fire going automatically and she can program it using an electronic controller.

 Judith fills her pellet boiler 

A convenient alternative
When the gas boiler in Judith Thornton’s 5-bedroom house needed to be replaced, Judith opted for a pellet boiler as a convenient, efficient and climate-friendly alternative. Some of the heat from the pellet boiler directly heats the room the boiler is located in while most of it goes into the central heating system which connects the boiler to radiators and the hot water cylinder in the house. Just as with a gas boiler, the heating system can be programmed through an electronic controller. The pellet boiler automatically feeds the fire and uses microprocessor-controlled fans for optimum efficiency.


pellets are made from compressed sawdustBag-by-bag or in the hopper
Judith’s boiler has to be filled with wood pellets manually, by filling pellets from a 15kg bag directly into the boiler. An alternative would be to use a pellet boiler that is fed automatically from hopper. Pellets can be delivered by truck and pumped into the hopper – so it is possible to use this form of wood heating completely without manually moving the pellets!

Judith estimates a 15 kg bag of pellets is enough to heat the house for one or two days during the heating season. In the winter of 2008/09 she used a total of 1000 kg (67 bags, around 4900 kWh units) of pellets, though a typical UK household would probably need twice or three times that much. In 2009 pellets cost around £250 per 1000 kg incl. delivery, or 5p per kWh of heat – a bit more than oil or mains gas, comparable to LPG and a lot cheaper than electricity.

a pellet stove with back boilerFinancial and environmental benefits
Judith paid around £4,000 for her boiler and got a £1,500 grant through the Low Carbon Buildings programme. From 2011 on, a pellet boiler system of this type could be eligible for support under the Renewable Heat Incentive scheme.

Wood is a renewable source of energy. And if it is sourced from sustainable forestry where a new tree is planted for every tree that is cut down then using wood for heating can be a good way to reduce CO2 emissions. Greenhouse gas emissions for pellets are around 90% lower than for oil or gas, so installing a wood heating system can reduce your household CO2 emissions by several tonnes!

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  • Biomass Energy Centre - http://www.biomassenergycentre.org.uk/ -
      UK government information centre for the use of biomass for energy. Has some details & links for government schemes to promote biomass equipment and fuels.
  • Microgeneration Certification Scheme - http://www.microgenerationcertification.org/ - 020 7090 1082
      The Microgeneration Certification Scheme (MCS) certifies microgeneration products and installers. MCS accreditation is required for Feed-in Tariff and Renewable Heat Incentive support.