Biomass Boilers

Ethical shopping guide to biomass boilers, from Ethical Consumer.

Ethical shopping guide to biomass boilers, from Ethical Consumer.

This is a product guide from Ethical Consumer, the UK's leading alternative consumer organisation. Since 1989 we've been researching and recording the social and environmental records of companies, and making the results available to you in a simple format.

We're sorry but the score table for this report has been removed because it is out of date.

  • Ethical and environmental ratings for 26 biomass boilers
  • Best Buy recommendations
  • which is the most sustainable fuel
  • all about the Renewable Heat Incentive
  • profiles of selected companies

Best Buys

as of July/August 2011

As our ratings are constantly updated, it is possible that ratings on the score table may have changed since this report was written.

All those companies that only produce innovative environmental alternatives have been awarded best buys in this sector: Eco Angus, Effecta, Solarfocus, Therminator, Woodpecker, Twinheat, Froling, Guntamatic, HDG.

Of those listed, Froling has the highest SAP energy rating.

Last updated: July/August 2011 



Costs and savings


A typical automatically-fed pellet boiler for an average home costs around £11,500 including installation, fuel store and VAT at 5%.

If you replace solid fuel or electric heating you could save between £170 and £390 per year.

Fuel savings are less significant if you replace a gas heating system with a wood burning one. Wood costs often depend on the distance from your home to a wood supplier and whether you can buy and store wood in large quantities. Typically heating and hot water costs for a year will be around £1,000 in a detached property.[8]



Emissions savings


You could save up to 9.5 tonnes of CO2 per year if you replace a solid (coal) fired system or electric storage heating with a wood burning boiler.[2] For those still using liquid fuel, one tonne of wood pellets can replace 400 litres of oil; saving 1072 kg of CO2.[4] It has been estimated that the country’s carbon emissions could be reduced by three million tonnes a year if biomass was used to provide heating for the UK (the equivalent of taking 3.25 million cars off the road).[5]

Burning biomass fuel does release CO2 into the atmosphere. However this CO2 has only recently been absorbed by the biomass and will be reabsorbed if replacement crops are planted, as a balance of carbon is maintained in the atmosphere. As long as new plants continue to grow in place of those used for fuel, the process is sustainable in terms of CO2. This differs from fossil fuels as these release carbon that has been stored away in the earth for many millions of years and increase the amount of overall CO2 in the atmosphere.

For domestic biomass boilers, wood (in the form of pellets) is the most common source of fuel but burning waste wood can be a good way of diverting matter from landfills. Some emissions are caused by cultivation, manufacture and transportation so try to source fuel locally and use waste wood where possible.



Energy ratings


Biomass boilers have a SAP energy rating. SAP 2009 annual efficiency, is an estimate of efficiency when installed under typical conditions in Britain, taking into account climate, housing conditions, occupancy patterns, and controls. You can see the ratings at



Air quality and planning issues


As well as water vapour and CO2, wood smoke contains traces of carbon monoxide, particulate matter and volatile organic compounds. Particulates cause a health concern in that their small size means they can enter your airways and cause burning eyes, runny noses, and illnesses such as bronchitis. Burning well-seasoned (dried) wood releases less smoke. Also, young and old people, particularly those that are ill, are most at risk, so limit their exposure to wood smoke if you can.[7]

Due to the smoke produced by the burning fuel you can’t use biomass boilers in Smoke Control Areas. These are usually situated in cities and were initially set up to reduce the impact of industrial emissions in or near densely populated areas. For example, virtually the whole of London is a Smoke Control Area. To find out if you live in an SCA contact your local authority.

Biomass boilers do not require planning permission unless the flue:

•    Exceeds 1m above the roof height.

•    Is installed on the principal elevation and visible from a road or is in a conservation area or world heritage site.



Other issues to consider


You’ll also need a large dry area close to the boiler to store your wood and a vent which is specifically designed for wood fuel appliances. Biomass boilers also require an annual inspection and produce a lot of waste ash. This, however, can be used as a fertiliser. You may also want to have an automated feeder so you don’t have to keep filling it up with fuel.





HETAS are the official body recognised by Government to approve biomass and solid fuel domestic heating appliances, fuels and services including the registration of competent installers. It is similar to the CORGI registration for gas fitters. Always use a HETAS registered installer.

You can find an installer near you using the website or email or call 0845 6345626.




The Renewable Heat Incentive



Launched in March 2011, the Renewable Heat Incentive offers money towards installation costs as well as payments for heat generated. Peter Bartley from CHB Sustainability explains more.


The Renewable Heat Incentive is an initiative similar to the feed-in tariffs for electronic generation, which aims to encourage the installation of renewable heat equipment in the UK. Unlike the Feed in Tariff though, it will use a whole-house approach which integrates both energy-efficiency and heat generation, so as not to encourage excess production of heat.

It is open to everyone (including homeowners, landowners, businesses, schools hospitals and entire communities who have joined up to invest in these technologies), and applicable to several different technologies, including biomass, solar thermal, heat-pumps, on-site biogas, deep geothermal, energy from waste and injection of biomethane into the gas grid.

There are three steps involved:
Step One: you install in your property renewable heat systems such as solar thermal panels, heat pumps or a biomass boiler
Step Two: you measure how much heat your renewable energy systems produce
Step Three: you get paid a fixed amount based on that output, the type of technology and the size of the system.

It will be introduced in two phases:

1) Beginning in July 2011, this will include upfront one-off payments (the Renewable Heat Premium Payment) to homeowners to reduce the initial capital cost of investing in renewable heat technologies.
This will be similar to Feed in Tariffs for renewable electricity with an annual payment based on the amount of renewable energy generated.

2) The second phase will benefit those who have installed an eligible technology since 15th July 2009; therefore it is a great idea to take advantage of phase one to get an upfront grant as you will still be eligible for annual payments from October 2012 when phase two commences.
Details of the phase two payments are unknown at the moment but are expected to be of the scale to give simple payback on investment within 15 – 30 years.

When considering any renewable energy technologies it is essential to ensure that you have already exhausted all the straight-forward energy efficiency measures that you can, such as insulation, draught proofing and low energy lighting. There’s no point generating renewable energy just to waste it!

It is expected that Energy Performance Certificates will be used to judge whether homeowners have suitably well-insulated homes in order to be eligible for the financial incentives. Homeowners should also ensure that both the renewable heat technology products and installers are accredited by the Micro-generation Certification Scheme (MCS) both to gain the financial benefits of the RHI, and ensure that the products and installers are reputable. Products certified under the Solar Keymark are also eligible for the RHI, but this certification doesn’t cover installers, so you’ll need to make sure your installer is certified under MCS.



Typical Cost
Typical Annual Saving *
Typical Annual CO2 Saving *
Upfront RHI Grant **
Solar Thermal
Service by accredited installer every 3 – 5 years
250 kg
Ground Source Heat Pump
£9,000 - £17,000
Service by accredited installer every 3 – 5 years
£70 (300% efficient)
750 kg
Biomass Boiler
Regular cleaning but generally no servicing requirement
1000 kg

*Annual savings are based on comparison with a typical condensing gas boiler. Savings would be greater with more expensive and carbon intensive fuels such as oil or electricity. These savings do not include the benefits of the Renewable Heat Incentive.
**Phase 1 of the Renewable Heat Incentive is from July 2011 for the first 25,000 applicants (totalling £15m). These figures are based on the Government consultation and are not confirmed as yet.




FSC biomass fuel


How do you know that your wood fuel is coming from a sustainable source?

At the moment, the Forest Stewardship Council (FSC) label is the only sustainability accreditation system for wood fuel. There are hundreds of fuel suppliers – the National Energy Foundation lists 954 for wood pellets alone – but just five are listed on the FSC website as having accreditation. Charles Thwaites, Executive Director of FSC UK, told Ethical Consumer that this is an “emerging market” and that many of the companies involved were newly formed and weren’t necessarily as ethically advanced as many of the FSC-certified companies in other sectors. He added that FSC was now “coming under increasing pressure to raise awareness in the biomass market.”

However a lack of accreditation does not mean that a product is unsustainable, just that the sustainability of its sources has not been verified independently. Some may be using waste such as mill by-products or from tree surgeons. The Forever Fuels website suggests that “you should not dismiss wood pellets that are not FSC or equivalent certified, but you may want to ask more questions about their provenance.”[3]

The campaign organisation Biofuel Watch, however, issues a note of caution. They state that, “no credible certification scheme (including the FSC) exists or has been proposed which is able to preclude serious environmental and social harm” from biofuels including wood chip and pellets.

BioFuel Watch (BFW) take issue with large-scale takes up of biomass, but stresses the knock on effect this will have within the domestic market. For instance last year, Drax, Britain’s largest power station, mixed its regular fuel coal with 300,000 tons of elephant grass to reduce its carbon emissions. Almuth from BFW told us: “We campaign against large biomass power stations and subsidies for them. Given the unsustainable scale of the biomass demand being created in the UK, we are also opposed to biomass subsidies under the Renewable Heat Incentive (RHI). As far as biomass boilers are concerned, it’s a question of scale, especially of the scale of the cumulative demand.”

BFW argue that the RHI will have an adverse effect on the environment by subsidising bio-fuels when they are likely to slow the rate of de-carbonisation. They describe them as an “unsustainable ‘high-carbon’ renewable.”
They question the carbon savings from biomass quoting the European Environment Agency’s Scientific Advisory Body who say, “the accelerated destruction of rainforests due to increasing bio-fuel production can already be witnessed in some developing countries. Sustainable production outside Europe is difficult to achieve and to monitor.” They add that increasing the use of bio-fuels is, “an experiment, whose unintended effects are difficult to predict and difficult to control.”[6]

They say that by including biomass in the RHI it will be a disincentive for people to use truly sustainable forms of renewables that can give real carbon savings. They cite importing woodchips and wood pellets, rather than using solar thermal or other types of energy, as a major problem.

They add that impacts of “uncontrolled large-scale biomass expansion are likely to be worse than those of the fossil fuels they replace.” The impacts of liquid fuels (oil) in the developing world both on food prices and biodiversity have been well documented, and they claim these will be “replicated and greatly worsened by the new trade in woodchips and wood pellets.”

Almuth also added a warning to consumers: “We think there’s a high risk that people investing in domestic biomass boilers and stoves will soon find themselves out-competed by big energy companies such as RWE and Drax and see wood pellets become ever less affordable (with steep price rises forecast for example by the forestry industry association Confor).”


Quality of pellets

HETAS assess wood products against voluntary European standards to ensure a high standard of fuel. Its Solid Biomass Assurance Scheme accredited fuels must be free from any chemical treatment and only contain woody matter. SBAS offer a labelling scheme to let consumers know about the moisture content, length, species of wood, pack size and country of origin. It also checks for consistency in fuel.

This ensures that you get wood with a moisture content of less than 25% (meaning less tar in your flue or on the windows of your stove).

As yet there is no legally required Europe wide quality standard.[1] A number of European countries (Austria, Sweden and Germany) have official standards specifically for compacted biomass fuels so if you do buy imported fuel from one of these countries look out for their standard.





Company profiles


Most of the companies that manufacture biomass boilers are small or medium sized companies. Most did not have either environmental reports or any supply chain policies. However, nine companies only produce ‘environmental alternatives’ and so are marked less stringently on the table, receiving a positive Company Ethos mark.

The largest company covered on the table, BDR Thermea, is the third largest heating equipment supplier in Europe and was the only company to pick up extra marks in another category, namely Human Rights, for having facilities in China and Russia which are governed by oppressive regimes.













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