Biomass heating systems run on wood logs, chips or pellets and are ideally suited to larger or older properties where a heat pump cannot produce sufficient heat quickly enough to overcome the heat loss of the building. They can also be used for commercial heating processes where a higher temperature heat is required.

Although they can be considered ‘carbon neutral’, because they only emit the carbon dioxide that is absorbed when the wood is growing, it is important to consider the fuel source and how far it has travelled between felling and burning. A reliable source of local fuel would be the most environmentally sound solution.

The wood fuel supplied is grown in agricultural forests, which are harvested and re-grown. The burning process generates ash, water vapour and CO2. All of these are used to re-grow organic matter. Since this cycle lasts 10 – 15 years it is deemed to be CO2 neutral. This compares with fossil fuel, which has a recycling period of millions of years.

Biomass heating systems can be adapted to many needs: from small domestic dwellings to large commercial applications and buildings. However, the 3 main types of biomass heating have different implications for the customer:


Log boilers are suited to those who own or have ready access to large volumes (tonnes) of wood that they can cut to size and season well. The boiler would need to be manually filled with logs roughly once a day, depending on the season, and burnt over several hours with the heat output being stored in a large well-insulated accumulator tank which can store 1000’s of litres of hot water. This accumulated hot water is then used over a longer period to provide space heating and domestic hot water maybe over several days in spring and autumn.

Wood chip

Wood chip boilers are more automated as the chip can be automatically fed to the boiler by a silo and auger screw. There would need to be a suitably large storage area to keep the wood chip dry and house the mechanical handling equipment to feed the silo. There is normally a certain amount of heat storage in hot water buffer tanks which is used to provide a fairly instantaneous source of heat, and to ensure that the boiler runs more efficiently by keeping it running as long as possible and reducing the number of firing cycles.

Wood pellet

A wood pellet boiler is similar in many ways to running an oil heating system with pellet fuel deliveries every few months which are either blown into a silo directly from a delivery lorry or delivered in bags for the customer to manually fill a smaller hopper in close proximity to the boiler. The boiler is fully automatic with self-cleaning cycles and if a silo is used will fill the day hopper from the silo either by an auger screw or blown air. As with wood chip, buffer tanks are normally used to ensure that the boiler runs more efficiently by keeping it running as long as possible and reducing the number of firing cycles.

All three types of wood gasification boilers are very efficient and control the burn process accurately to extract the maximum energy from the fuel and produce very little ash.

Biomass boilers operate differently depending on the type deployed but in general their benefits include:

  • Potentially Lower Heating Bills, when compared to previous oil, LPG or all-electric systems
  • Renewable Heat Incentive
  • Mitigate Escalating Fuel Prices
  • Reduced Carbon Footprint
  • Easy to Retro-fit with Existing Radiator System
  • Ideal for properties with high heat loss