So you've installed an extractor fan, but your bathroom is still getting condensation – what now? While this might be a confusing situation to be in if you feel like you've done all the right steps, there could be some other factors at play.
Condensation forms when moisture-heavy air hits a cold surface, which is why bathrooms are so prone to it, especially in winter. The best bathroom extractor fan should help to reduce it, but it can't remove it directly, and there may be other reasons why you're getting so much.
If you want to get to the bottom of the condensation in your bathroom and tackle it before it becomes a mould and damp problem, you'll want to read our expert advice below.
1. Your extractor fan isn't working properly
Just because you have an extractor fan, it doesn't necessarily mean that it's up to the job – and there are several reasons why it might not be working:
It isn't powerful enough: "Your fan needs to suit your bathroom and its ductwork," explains Rob Stevens, Ventilation and HVAC Expert at Aspect. "If the extraction rate is too low, it will struggle to clear moist air quickly enough."
Fans that switch on and off should have a minimum extraction rate of 15 litres of air per second, according to guidance in England, but you can also use a free online calculator to estimate the airflow required for your space.
It isn't running long enough to remove the moisture: If you have an extractor fan with a humidity sensor, you won't have to think about this, but Michael Zohouri, founder of Pyramid Eco, suggests leaving it on for at least 20 minutes after your shower.
It is blocked with debris: Your extractor fan will struggle to remove moisture from the air if it's clogged up with dirt and dust, which is why Michael says cleaning it out as needed is so important. Our guide on how to clean a bathroom extractor fan will teach you how to do so safely.
The room isn't getting enough replacement air: To ensure your bathroom has enough airflow for the fan to work properly, Michael says the room shouldn't be airtight, and there needs to be a sufficient gap beneath the door.
It's fitted too low: "Warm, moist air rises, so the extraction point should be as high as practical, on the ceiling or no more than 40cm below it," says Rob Stevens. "If yours is positioned much lower it might be worth getting advice to see if it can be easily moved to a higher position."
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Damian Wallis is Dryzone’s resident mould, damp and ventilation expert with over 20 years of experience. He specialises in identifying and addressing the root causes of mould, mould prevention and removal.
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.
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. The surfaces are particuarly cold
While condensation can be a sign that your extractor fan isn't working properly, it might just mean that your surfaces are particularly cold – especially if your home is poorly insulated and there's a lot of moisture in the air.
"Even with good ventilation, some condensation can still form on particularly cold surfaces, especially during winter," explains Damian Wallis.
However, if condensation is regularly building up and you notice black spots or musty smells, it's well worth investigating further.
Other ways to reduce condensation
If you're looking for other ways to reduce condensation alongside your extractor fan, you could try:
1. Opening your window during or after a shower: This will help to remove humid air, explains Damian Willis, and works well when combined with wiping down wet surfaces afterwards.
2. Wiping the condensation away: Using the best window vac or a squeegee, wipe the condensation off your windows, mirrors and tiles, and dry any remaining wet patches with an absorbent cloth, recommends Rob Stevens.
3. Using your fan's boost setting (if it has one): "This increases extraction to remove humid air more quickly, helping existing condensation evaporate and reducing the chance of more forming," explains Rob. "If your fan doesn’t have a boost setting, keep it running at its normal speed to help the room dry out."
As annoying as it is, condensation is very common in bathrooms. However, by following the steps above, you can help to reduce it.
For more advice, read our guide to normal humidity levels in a house or learn how to stop condensation in your home.
