Is your stove doing more damage than you know? We reveal the least-polluting fuels

If you have a multi-fuel or wood-burning stove in your home, it's important that you use it responsibly by burning fuels that are more efficient and will create less pollution.

Of the 1,434 stove owners we surveyed in January 2018, 5% burn wet wood on their wood-burning or multi-fuel stove, and 4% use house coal. These numbers might seem small, but these are two of the most polluting fuels, with wet logs also being extremely inefficient.

Read on to understand how you can avoid creating additional pollution, and keep your stove cleaner in the process, plus get some money-saving tips.

If you're thinking of buying a stove, find out the pros and cons of electric, gas and wood-burning stoves.

Types of fuel for your multi-fuel stove or wood burner

To find out how much stove owners really know about the fuels they should be using, we asked what they think are the best fuels for:

• producing heat
• keeping costs down
• minimising pollution, and
• keeping a stove clean.

The majority of stove owners we spoke to (81%) use seasoned logs, followed by kiln-dried logs (35%) and smokeless coal (22%):

• Seasoned logs are ones that have been dried out - you can buy them already seasoned or you can season logs yourself at home.
• Kiln-dried logs have been dried out by firing them in a kiln.
• Smokeless coal or fuel is usually (although not always) manufactured and can come in a variety of different forms - more on this below.

Technically, all three can be efficient, depending on the type and how dry they are.

Wet logs can be collected (say from your garden) or bought, but shouldn't be burnt. Their high moisture content of between 60% and 80% means that energy will be wasted burning off water before the log itself.

This will also create more pollution, as well as build-up in your chimney, which could lead to it being a fire hazard.

As a rule of thumb, only burn wood with a maximum of 20% moisture - the lower the better.

What about burning coal?

It's a similar story with bituminous house coal with regards to pollution, particularly if the sulphur content is 2% or higher.

Smokeless coal or fuels, on the other hand, are much more environmentally friendly. Because they're hard, they have a high carbon content and don't contain volatile materials, they're efficient and don't produce as much smoke.

One form of smokeless coal is anthracite, which is naturally occurring. Manufactured smokeless fuels tend to use anthracite as a base, which is ground down into a powder. This is then formed into briquettes (compressed blocks) using a smokeless binding agent, such as starch or molasses.

Visit our page on stoves and pollution to learn more about the effect stoves have on the environment and what you can do to minimise it.

What's the price of wood and smokeless coal?

Wood

To give you a rough idea of the price of wood, we've looked at a number of online suppliers*.

• Seasoned logs - around £116 per cubic metre.
• Kiln-dried logs - around £135 per cubic metre.
• Briquettes made of crushed paper or wood are usually sold by the kg and cost around £150 per 500kg.

As you can see, seasoned logs are cheapest. Some seasoned logs will have only been partially dried out and might have around 25% to 40% of moisture still in them.

If you choose to buy these, you will need to dry them out further at home before you burn them. To do this, you will need to have space somewhere where the wind can get to the logs but moisture can't. You can buy specialist log stores for this.

Even cheaper would be to buy freshly cut logs (these cost around £100 per cubic metre), or to even find them, and then dry them out yourself. If you're collecting wood, make sure you have permission to do so and that it's not been treated with any chemicals.

Also keep in mind that drying wet wood can take as long as two years, depending on how wet it is and the conditions you dry it in. You can buy a moisture meter to check when they're ready.

Alternatively, if you don't mind spending a little more, kiln-dried logs have around 20% moisture, and briquettes around just 10%, so you won't have to dry them yourself and can burn them straight away.

Look out for the Ready to Burn logo, a government-backed scheme that certifies that wood has less than 20% moisture.

Coal

Looking at online suppliers, we checked for the average price of natural anthracite coal and smokeless fuel.

• Anthacite coal - around £422 for 40 25kg bags of large anthracite nuts and £415 for the same amount of small nuts.
• Smokeless fuel - from around £285 to £580 (£440 on average) for 40 25kg bags.

You can buy 25kg bags individually, or in tens and twenties, but they will be a little more expensive. Also, these prices are excluding delivery, which may change the price depending on where in the country you live.

As the price range for smokeless fuel shows, it comes in a lot of different forms. There are a variety of shapes and sizes available, and different mixes of materials.

Our page on multi-fuel and log burner costs details more about the price of different types of fuels as well as more tips on how to save money.

Use and maintain your wood burner or multi-fuel stove correctly

Burning the right fuel on your stove is only half of the story when it comes to efficiency. You also need to make sure you're using your stove correctly and maintaining it.

Get your chimney swept every year before using it to remove any soot or tar build-up. Ask your chimney sweep to also check the stove for any cracks, distortions, holes or rust, and get problems fixed before use.

Make sure you know how to properly use and control your stove so that it doesn't smoke.

Visit ourpage on using a log burner or multi-fuel stove to watch our videos on burning wood or coal in a stove to ensure you're doing the right thing.

*The prices for the logs are for a mix of softwoods (pine and fir, for example), and hardwoods, such as oak, ash, beech and birch. All sites deliver across the UK, and the prices for seasoned and kiln-dried logs don't include delivery, but the price for briquettes does.