How often should you sweep your chimney? Experts reveal all

Once the cold weather arrives, few joys compare to that of a working fireplace for creating a cosy, ambient setting to stay snug. However, whether you have a roaring open fire or a log-burning stove, it does mean you should have the chimney swept before you can start using it.

Sweeping the chimney is an essential home maintenance job that ensures your house is not only safe when using the fireplace, but also that the fuel burns more efficiently to keep your house warm.

"Getting a professional chimney ‘health check’ will ensure that your flue pipe or chimney is clear and safe when you re-light your appliance in the colder months," explains Jon Butterworth, Director at Arada Stoves

But how often should you sweep your chimney? We've asked our team of heating experts to share their guidance to ensure we're all keeping on top of things.

How often should you sweep a chimney?

"We recommend having your chimney swept at least twice a year when burning wood and at least once a year when burning smokeless fuels, such as briquettes or smokeless coal," advises Serena Sumner, head of service delivery at HETAS.

Explaining the reasoning behind these timelines, Serena says, "Burning wood or smokeless fuels leads to a buildup of soot, creosote, and other flammable substances, making an unswept chimney a fire risk. Lighting your fire with an unswept chimney puts you in danger and can have devastating consequences."

Jon agrees, saying: "I’d advise having this (a professional sweep) done at least once a year, so aim to organise it at the start of autumn if you haven’t already had it done this year. This will result in your stove working efficiently and safely, while preventing the build-up of soot in the flue or chimney, which, if not properly maintained, can cause a fire."

"We’d also recommend having your stove professionally serviced at the same time," suggests Serena. "Servicing includes checking over your stove for any faults – including fraying rope seals, cracked firebricks, or defective air controls – and fixing them to keep your stove running optimally."

The best time to have your chimney swept is just before the start of autumn, when the heating is switched back on, after the fireplace or stove has remained dormant over the spring and summer months.

"If you’re planning on sweeping your chimney on a yearly basis; as long as your stove is not in active use for a prolonged period, you plan ahead during a warm springtime might also be a good time to have this done," suggests Jon.

"If sweeping twice a year, the second time should be after the peak of the main heating season, as the weather begins to warm up, around April or May," suggests Serena.

Serena Sumner

With over a decade of experience in the industry, Serena leads on business development, training and registration teams across HETAS – a not-for-profit organisation leading the way in training, education, certification and testing across the solid fuel, wood and biomass heating industries.

How do you know if your chimney needs sweeping?

Out of sight, out of mind is the problem with chimneys, because you can't see that they require cleaning. Keeping an annual record is the easiest way to determine if and when it needs sweeping, but there are also a few telltale signs, as Serena highlights below.

"If you experience any of the following signs, stop using your appliance and book a sweep as soon as possible..."

• Smoke is re-entering the room when the appliance is in use.
• There is a persistent bad smell when you have not lit a fire.
• You can see signs of tar around the flue entrance or in your appliance.
• Soot or debris is falling back into your appliance.
• Your fire isn’t burning as well as usual and you haven’t changed anything.
• You often see birds by the top of your chimney or hear frequent scratching (there may be birds nesting in your chimney).

What is the average cost of a chimney sweep in the UK?

The cost of having your chimney swept will differ from household to household, but mine cost me £70 last November – which reminds me to book in soon.

Serena agrees, saying: "Costs can vary based on where you are based in the country and also the level of work undertaken; however, expect to pay between £90 and £120 per chimney, with costs increasing if there are large buildups to remove or extra work required."

Is it a legal requirement to have your chimney swept?

"There is no legal requirement in the UK to have your chimney swept," says Serena. "However, it should be a part of responsible stove ownership and fireplace management. A swept chimney is significantly safer and lets you heat your house more efficiently."

It’s also worth noting that many home insurers will also expect your chimney to be maintained as part of your insurance policy. "Especially if you have a real fire or stove in use," says Serena. "Failure to do so could invalidate your insurance, and claims could be rejected if the worst happens."

To confirm this, we asked Alex Cross, Chief Customer Officer at Tesco Insurance, who told us: "Insurance policies usually expect that you look after your property and take steps to prevent damage or allow it to get into disrepair. Not only can neglecting important upkeep, such as not cleaning a chimney flue affect claims, it could also become a fire risk,"

"Undertaking regular home maintenance either yourself or through a qualified tradesperson is essential to keep it safe. It’s a good idea to check your policy carefully and ask your insurer if anything isn’t clear. Staying on top of maintenance helps protect your home and gives you peace of mind, knowing you’re covered if the unexpected happens"

Once you have had your chimney swept, you get a 'sweep safe chimney sweeping certificate' proof, if needed, for your home insurance provider that you have carried out the safety checks. This certification also gives you peace of mind and the confidence to keep your home fires burning.

It's also worth exploring what the experts recommend as the best wood to burn in a log burner to help keep your appliance running as smoothly as possible.