Biomass boiler costs: How much will this gas boiler alternative cost?

green biomass boiler with large hot water tank
(Image credit: Getty Images)

Biomass boiler costs will be a big factor when deciding whether to invest in this alternative to gas and oil boilers.

The two big advantages of operating a biomass boiler in your home to drive your heating are that biomass is more environmentally and climate friendly than oil and gas and, secondly, the biomass fuel, at present, costs less.

As with many renewable energy systems, the major initial hurdle is the installation cost, but there are, under certain circumstances, grants of up to £5,000 available under the government’s Boiler Upgrade Scheme to assist with this.

This guide breaks down the key costs, including the capital cost, ongoing maintenance fees and fuel costs.

How much does a biomass boiler cost? 

The cost of a biomass boiler varies according to the size of the boiler and the type of fuel it burns, typically ranging somewhere between £4,000 and £21,000. However, the average cost is currently around £16,000. 

If the boiler is automated, such that fuel is fed automatically into it, this too will bump up the cost, with automated models costing significantly more than manually fed models. The benefit however is having a system which is lower maintenance.

The installation of a biomass boiler will also require the fitting of a hot water storage cylinder, if you don’t already have one. 

Properties with existing combi boilers will not have a water cylinder and so one will have to be fitted, along with all the associated pipework. This could increase the installation costs by £1,000-£2,000. 

This will be in addition £200-£250 per day installation charge levied by a professional biomass boiler installer fitting the biomass boiler. The installation will usually take one to two days to complete.

How much could I save with a biomass boiler?

The average biomass boiler that burns wood pellets currently costs around £15,000 to £16,000, compared to circa £2,000 for an oil-fired boiler and £2,000-£3,000 for a gas-fired boiler. However, when it comes to fuel costs, biomass fuel is much cheaper, with wood pellets costing 3 pence per kilowatt hour (kWh) compared to around 9.3 pence per kWh for an oil-fired boiler and 10.3 pence for gas. 

Installing a biomass boiler can also save up to 40% on your energy bill as a gas boiler alternative, although this depends to some extent on various factors, such as the size of the house and the amount of energy needed to heat it. In general, once it is up and running, a biomass boiler will be much cheaper to run than oil, gas and electricity.

A biomass boiler can also displace around 9 tons of carbon emissions per year and may increase the value of your home as homebuyers are increasingly prioritising properties with renewable energy systems installed when making buying choices.

biomass boiler with fire burning

(Image credit: Getty Images)

How much is a small biomass boiler?

The size of the boiler depends on the amount of space for storing the biomass fuel, which means that biomass boilers tend to be larger than other types of boiler. The cost also depends on the type of fuel, whether it is pellets, chips or logs.

  • A small manual-fed log-burning biomass boiler usually costs £5,000-£13,000
  • A large manual-fed log biomass boiler costs £13,000-£16,000
  • A small automated pellet biomass boiler costs £15,000-£21,000 
  • A large automated pellet biomass boiler costs £22,000-£31,000

How much does biomass boiler maintenance cost?

A biomass boiler will require a professional service at least once a year and current costs for this range between £180 and £450.

Burning wood fuel always produces some ash, which falls into an ash pan. This needs to be removed every one to four weeks, but it can be used as fertiliser in the garden or fed into a compost heap. Dry, high-quality fuel will produce less ash but might cost you more overall.

How much does biomass fuel cost?

There are three different types of wood fuel, specifically pellets, chips and logs. 

  • Wood pellets usually cost £245 per tonne 
  • Wood chips cost around £59 per tonne 
  • Logs around £99 per tonne

It’s a good idea to buy fuel in bulk to keep costs low. A wood pellet biomass boiler in an average house will usually use 2-5 tons of wood pellets across the winter.

Wood chips are less dense than pellets and therefore are more expensive to transport, and they need more space to store them. For this reason, they are usually not suited to domestic premises.

Wood pellet and wood chip biomass boilers are often automated, via a nearby hopper, and so do not require manual feeding, but will need more space (around 10m2) and will be a more expensive initial investment. 

Can you get a grant for a biomass boiler?

Under certain circumstances, grants of up to £5,000 are available to help with biomass boiler costs under the government’s Boiler Upgrade Scheme. However, this grant is limited to properties in rural locations that are not connected to the gas grid. 

These properties also need an emissions certificate to show that polluting emissions will be minimised. Self-build properties are not eligible for this grant.

Grants were previously available under the Renewable Heat Incentive, but this government scheme ended in March 2022. Anyone who managed to sign up for it before the scheme ended will receive quarterly payments for seven years.

Robin Whitlock
Freelance journalist

Robin is a freelance journalist based in the South West of England, UK. He specialises in environmental issues, climate change and renewable energy, with other interests in transport and green motoring. He is a regular daily correspondent for a renewable energy website, writing news articles and interview pieces on all the main clean energy technologies. He has also written widely for numerous magazines on these topics, as well as writing white papers and web content.