4 warning signs your bathroom extractor fan isn't working as well as it should
From rattling noises to excess condensation, ventilation experts reveal the signs it's time for a new bathroom extractor fan
If you've noticed damp, mould and lingering condensation in your bathroom, it could be a sign that it's time to replace your extractor fan – or you may find these problems worsening over time.
The best extractor fan helps keep your bathroom free from damp and nasty odours, which is why ensuring it's in tip-top condition and doing its job properly is key.
Below, our ventilation experts reveal the four warning signs that your extractor fan is in need of an upgrade, so you can get your bathroom feeling fresh and dry once again.
1. Lingering steam and condensation
Does your bathroom stay steamy long after you've finished your shower? Is your mirror completely foggy? Does condensation run down the walls?
If the answer is yes up to half an hour later, Michael Zohouri, founder of Pyramid Eco, says these could be signs that your bathroom extractor fan is not working as it should be.
The fan is designed to remove excess moisture from the air, so the fact that it's building up on your surfaces shows that something isn't right. While this doesn't automatically mean you need a new one, you should initially check whether it's dirty, incorrectly installed or the wrong size for your room.
Bathroom extractor fans we recommend
Voted the best option in our buying guide, this fan can extract 26 litres per second and received a Quiet Mark award for its low noise.
Consuming just 4.8W, this energy-efficient fan is well worth considering and has an adjustable timer.
Another favourite of ours, this ultra-quiet extractor fan features a ‘twist-and-click’ system, which makes it a breeze to install.
Michael Zohouri is the founder of Pyramid Eco, bringing over a decade of experience to the company. His expertise spans energy-efficient retrofitting projects, including insulation, solar and heat pump installations.
2. It's making unusual noises
Michael Zohouri says that unusual noises are another key sign that your bathroom extractor fan might be broken.
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If you've noticed any new rattling or buzzing noises that weren't there before, he warns that the motor or bearings might be on their way out. It may also take longer to start up or stop working intermittently.
3. There are black spots on your sealant or walls
When water vapour condenses on cooler surfaces (such as the walls, ceilings and windowsills), these damp conditions can cause mould spots to form on places like your bathroom sealant. This is another strong indication that your extractor fan isn't working efficiently – or at all.
"An underperforming extractor fan can allow moisture to build up in the bathroom," says Rob Stevens, Ventilation and HVAC Expert at Aspect. "Black spots that keep returning on sealant or nearby surfaces can be a sign that moisture is not being cleared effectively and mould is forming."
Rob is HVAC Trade Manager at property maintenance company, Aspect. He has more than 15 years’ experience across air conditioning, ventilation and mechanical ventilation with heat recovery (MVHR) systems.
4. Steam escapes when you open the bathroom door
"If you notice a cloud of steam escaping as soon as you open the bathroom door, it’s a sign that moist air is accumulating rather than being drawn outside," explains Rob Stevens.
Not only does this affect your bathroom (see the previous point), but it can also settle on colder surfaces in the rest of your home, such as bedroom walls, causing damp patches or dark spots of mould to appear.
Do I need to replace my bathroom extractor fan?
If you experience any of the signs above, then yes, there is a good chance that you'll need to replace your extractor fan. However, before you do, Michael Zohouri says you can carry out the following checks first:
1. Clean your extractor fan: "You'd be surprised how much dust builds up behind the grilles. Isolate the power before removing any covers, and only clean the parts the manufacturer says are safe to access."
2. Try the toilet paper check: "Hold [a sheet of toilet paper] against the extractor grille while it's running," he says. "If there's barely any pull, that suggests you're not getting much airflow. It's not a proper airflow test, but it's a useful first check."
If everything looks good but your extractor fan still isn't working, it could be worth calling in a professional to take a look.
Extractor fans play a vital role in keeping your bathroom fresh and damp-free, so it's important to get yours checked or replaced as soon as you notice any of these signs.
Found this helpful? You may also want to find out whether you can use a dehumidifier in the bathroom or how to identify damp in the bathroom. Or, read our guide to the signs and causes of mould in the bathroom, and the best ways to prevent it.
As Content Editor at Homebuilding & Renovating, Megan is passionate about providing expert-backed advice and creative inspiration to help readers transform their living spaces. Her love for DIY began while helping to renovate her parents’ family home, sparking a fascination with interiors, renovation, and design. More recently, she assisted with the renovation of her partner’s house in Bristol and is currently expanding her expertise through an Introduction to Home Improvement course. She joined the Homebuilding & Renovating team in 2025, having previously worked as a Staff Writer at PetsRadar and Beauty Assistant at Harrods.