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Home & garden.

Updated: 10 Jan 2022

Wood-burning stoves and pollution

We explain the pollution that wood-burning stoves can create, to help you make an informed decision about buying one. If you rely on a wood-burning stove, here's how to use it in the least polluting way. 
PF
Paula Flores

Wood-burning stoves are increasing in popularity – partly due to rising gas prices, and partly due to rising interest in cottage chic. But scientists are concerned about the impact on air pollution. 

Air pollution is the biggest environmental risk to public health in the UK, according to the Department for Environment, Food and Rural Affairs (Defra). 

In October 2021, we surveyed 1,375 Which? members who had bought a wood-burning stove in the past 10 years. 

Three quarters (74%) said they were concerned about the effect of wood-burning stoves on pollution levels. 

However, only a third (34%) believed there was a need to be concerned about the stove's impact on the health of those living in their household. And only 37% were concerned about the impact on their neighbours' health. 

Read on to find out what scientists and industry bodies have to say, and how you can create a rustic aesthetic at home without necessarily buying a wood-burning stove. 

You may be reliant on wood-burning. But, if you don't need a wood-burning stove, consider an electric fire or stove as an alternative.

Are wood-burning stoves bad for the environment?

Wood burning stove with a basket of wood logs nearby 481367

Defra's 2019 Clean Air Strategy says that:

  • Many people don't know that emissions in the home increase personal exposure to pollution and contribute significantly to national emissions. 
  • UK air quality has improved significantly over the past few decades – but this trajectory has slowed. Emissions from transport and industry have decreased, but emissions of other sources, including heating our homes, have become more significant
  • 38% of UK particulate matter (PM) emissions now come from burning wood and coal in domestic open fires and solid fuel stoves. This includes burning wet logs and house coal, both of which emit higher levels of PM than manufactured solid fuels and dry wood. 

This 38% figure has been challenged by the Heating Equipment Testing and Approvals Scheme (Hetas), which tests and approves fuel, stoves and installers, and the stove manufacturers' organisation, the Stove Industry Alliance (SIA). 

January 2020 research commissioned by Hetas and SIA claimed that the 38% might also include other types of unregulated burning, such as pizza ovens, fire pits and bonfires. 

Hetas and SIA also criticised the previous study's predictions around the amount of fuel burnt, and the methods used to measure PM levels.

More recently, the European Environmental Bureau (2021) claims that even Ecodesign stoves (stoves produced according to more stringent criteria - find out more on these later) produce PM pollution. 

SIA has responded by saying that these claims are overstated and that it's working on producing its own data showing how much PM2.5 is emitted by a wood-burning stove. 

No surprise, then, that homeowners are confused by the regulations around wood-burning stoves. In fact, we found that a significant proportion of our survey respondents weren't informed about their own stove's eco-credentials. 

A third of our survey respondents (35%) knew they had a Defra-exempt stove, 10% knew their stove had SIA certification, and 3% knew their stove had the most recent Clearskies certification. But more than half (55%) didn't know. 

In a separate survey, we quizzed 15 Which? members who had bought a wood-burning or multi-fuel stove within the past three years about their understanding of wood-burning stove regulations. 

One told us: 'The legislation is all over the place - building regulations, wood, '"hearth size" etc. They should put the regulations in one place and give out a printed copy with each stove sold.'

Owners have turned to a range of sources for advice, telling us:

'I know what I have read in the media and what my installer advised' 

'I have asked my wood burner installer who is certificated by HETAS about the new regulations and they have explained the detail to me.'

Research in the field is ongoing. But you should be aware of the potential risks before making a purchase. 

Is there going to be a wood-burning stove ban?

The 2021 Environment Bill aims to make it easier for local authorities to tackle pollution from domestic burning and to improve air quality. The government has said it wants to:

  • educate people who buy and use stoves
  • ensure cleaner fuels are burnt 
  • reduce the pollutants emitted by stoves.

However, the government has no current plans to completely ban wood-burning stoves. Campaign group Mums for Lungs is calling on the government to take much stricter measures, including:

  • phasing out the sale of new wood stoves by 2027
  • banning the use of wood burners, unless they are the only source of heat in a household, by 2023
  • labelling wood-burning stoves as harmful
  • empowering local authorities to stop unlawful burning
  • obliging owners of wood-burning stoves to register their stoves with the local authority, so that it's easier for local authorities to enforce the rules around them
  • launching a public health campaign to raise awareness of the dangers associated with wood-burning stoves.

Continue reading to find out more about what you can and can't currently burn. 

Wet wood and house coal are banned from sale

Basket of logs
As we said before, burning wet logs and house coal produces far more PM than burning dry logs and low-sulphur solid fuel, such as anthracite coal. House coal also produces high levels of sulphur.

Since 1 May 2021, the following should not be sold in England:

  • Wood with higher than 20% moisture content in bundles of up to 2 cubic metres
  • Pre-packaged bituminous house coal.

Instead, you should buy wood that has a certificate showing it contains less than 20% moisture. This will be labelled as 'Ready to Burn'.

Ready to Burn wood should show the logo, the supplier's name and its certificate number to prove the supplier is compliant.

Most suppliers are banned from selling small quantities of wood with more than 20% moisture. 

Some very small sellers have until May 2022 to stop selling small batches of wet wood.

Or it's possible to dry our own. You can still buy larger batches of wood to season (leave to dry) at home. Sellers must give you advice with it on how to store and season the wood until it's ready to burn.

Bear in mind that seasoning could take two or more years, depending on how wet the wood is to begin with and the conditions you store it in. You can buy a moisture meter to check the levels.

You can also buy loose house coal until February 2023. There is already a limit in smoke control areas on burning fuel that contains more than 2% sulphur. 

The government is working with industry, including Hetas, SIA and chimney sweep organisations, to tell stove owners about this when they buy fuel or have their chimney swept or maintained.

Rules for smoke control areas 

Electric stove in a living room with a cream sofa and black coffee table

Some areas are designated smoke control areas. In these areas, you cannot emit smoke from a chimney unless you're burning an authorised fuel or using an exempt appliance. 

These rules have been met with different levels of adherence, according to councils. If you live in a smoke control area, make sure that you understand what you can and can't burn in a smoke control area.

The government is working with local authorities and retailers to raise awareness of these rules when a stove is bought. 

The new Environment Bill also ensures smoke-control legislation is easier for local authorities to enforce and gives authorities more power around reducing pollution further in their area.

If buying a wood-burning stove, here's how to reduce the pollution it could create

Make sure your stove is efficient

New rules for minimum efficiency and maximum emission levels for stoves apply from January 2022. The Ecodesign Regulations mean that only stoves that have been tested and found to meet the new limits will be legal to sell and install in the UK. 

During the transition period, the SIA has been working with manufacturers to create stoves that meet the emissions part of the criteria. 

The SIA says these 'Ecodesign Ready' stoves emit fewer harmful particles than open fires and older stoves.

Stove Industry Alliance Ecodesign Ready logo
Hetas also lists stoves that can use its 'Hetas Ecodesign Compliant' logo: these meet the new limits for efficiency and emissions. 

Another certification initiative is Clearskies. This is run in partnership with SIA. Stoves are independently assessed for emissions and energy performance. There are different levels, from 2 to 5. Stoves from Level 3 onwards are also Defra-exempt and 'Ecodesign ready'. 

Find out more about how to buy a multi-fuel stove or log burner including how to navigate efficiency, wattage and building regulations.

Make sure your wood-burning stove is Defra-exempt

If you live in a smoke control area, you're only allowed to burn smokeless fuel – such as anthracite coal. If you want to burn wood, you'll have to buy a Defra-exempt stove (also called Defra-approved).

Even if you don't live in one of these designated areas, if you're buying a wood-burning stove, it's best to make it a Defra-exempt one. This is because these stoves fit government criteria regarding smoke and emission levels.

Wood creates more smoke if it doesn't have a good enough supply of oxygen. Defra-exempt stoves make it harder for wood to smoulder and stop it from ever being completely starved of oxygen. So, as well as reducing emissions, it will minimise soot build-up in your chimney. This will keep your flue clearer for gases to escape.

For a full round-up of all of the brands we've rated, visit our best wood-burning stove brands. You can also check the Defra website to find out more. 

Don't burn wet logs in your stove

Only burn wood with a moisture content of 20% or less: wet wood emits more PM when burnt then dry. 

Burning dry wood is more efficient, as energy won’t be wasted having to burn off the water first, so the heat output will be higher. 

It also minimises sooty deposits building up in your chimney, which can be a fire hazard.

Never burn treated wood, such as from an old piece of furniture, as it could let off toxic chemicals.

Our advice on using a log burner or multi-fuel stove tells you more about the different types of fuel, using them efficiently and the Ready to Burn logo.

Burn smokeless fuel instead of house coal

Burning smokeless coal is less damaging to the environment than burning house coal, as it produces fewer emissions. 

19% of stove owners who answered our survey burn smokeless coal regularly, though 2% still use house coal. 

Smokeless coal is an umbrella term for a few different types of coal that produce less smoke when they burn. It includes anthracite coal – this occurs naturally, but can also be manufactured.

Manmade smokeless coals can contain a combination of elements, including anthracite and other renewable materials, making many of them more eco-friendly than house coal.

Look for smokeless fuel with 2% or less sulphur, as high levels of sulphur can impact your health and damage stoves and chimneys. 

For smoke-controlled areas, the Clean Air Act 1993 states that smokeless solid fuels mustn't contain more than 2% sulphur. 

You should no longer be able to buy pre-packaged house coal in England. Manufacturers of solid fuel must put the Ready to Burn logo on packaging to show that it meets new standards for emissions and sulphur content.

Learn how to keep your stove burning well

Wood that doesn't have a good supply of air is likely to smoke more, therefore producing higher levels of potentially harmful emissions.

Whether you're burning wood or smokeless fuel, leave the door ajar and open air vents while you're getting the fire going. Once established, use the air vents to keep the fire burning.

Ensure the flue stays at the right temperature throughout use, by making sure the fire is constant. Stacking fuel into a teepee shape at the beginning will help. 

This will also prevent carbon monoxide – an odourless and potentially deadly gas – coming down the chimney. 

It's worth buying a stove thermometer to monitor the temperature. Most stoves should stay between 200°C and 250°C. This can vary for each stove, so check with your manufacturer.

Clean and maintain your stove regularly

Chimney sweep

Having your chimney swept regularly is vital for ensuring it doesn't get overloaded with sooty deposits. Any obstructions could become a fire hazard and will prevent smoke escaping from your home properly.

You should get it swept quarterly while it's in use if you burn wood or coal. If you burn smokeless coal, you should get it swept once a year. 

You should also have your stove serviced annually to make sure it's working efficiently and safely.

Worryingly, 3% of people we spoke to never get their stove swept. However, a high proportion (62%) get it swept annually, and 27% do so every few years.

You can find a chimney sweep and qualified installer via Which? Trusted Traders, Hetas, or the National Association of Chimney Sweeps.

Make sure you also examine your stove for any cracks, distortions or other problems and get them checked by a stove installer or chimney sweep. Any faults could mean harmful pollutants are making their way into your home.

 Find out more about air pollution at home by heading over to our guide on how to improve your indoor air quality at home.

Other ways to create a rustic aesthetic at home without buying a wood-burning stove

If you're not connected to the gas grid, then you might be reliant on home fires for heating. However, if it's more of a lifestyle choice, there are other ways to incorporate that Instagrammable cottagecore aesthetic into your home décor. 

Bring in living decorations, such as fresh flowers, houseplants and trailing vines. Check out our plants advice guides for help with planting and growing flowers, or, if you're a keen gardener, head over to our grow your own vegetables guide

One caveat: houseplants have many mood-boosting effects, but don’t rely on them to clean your air at home. You’d need vast numbers of house plants to make a discernible impact on your indoor air quality. Welcoming nature into your home can be beneficial to mental health, however. 

Floral patterned wallpaper, cushions, vases and rugs also help create a natural, soft look that can have a calming effect. 

To avoid spending too much, scour charity shops and ask your relatives and friends if they have any decorative plates, flower pots or soft furnishings they no longer want, but that you could make use of. 

Reusing and recycling ornaments means they are authentically retro, and is more eco-friendly than buying new. 

Check out all our guides to decorating and DIY