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Bathroom + laundry exhaust fans video

Mould on the ceiling with the fan on?

The short answer

Mould can grow on a bathroom ceiling even with the fan on because a running fan isn't always extracting: if it dumps moist air into the roof, or is too weak for the room, the moisture stays. Run it during every shower and for 15 to 20 minutes after, and make sure it vents outside.

  • Bathroom + laundry exhaust fans
  • 0:30 Short
  • Published 29 Oct 2026

7 days a week. No call-out fee, and you pay after the job.

Key points

  • A fan that is running isn't always a fan that is extracting.
  • If it dumps moist air into the roof, or is too weak for the room, the moisture stays.
  • Run it during every shower and for 15 to 20 minutes after. A timer makes that automatic.
  • Check first that it actually vents outside.

Questions this video answers

Why is there mould on my bathroom ceiling when I use the fan?

The fan may be running without extracting. If it vents into the roof space or is too weak for the room, the moisture stays and feeds mould.

How long should a bathroom exhaust fan run after a shower?

Run it during every shower and for fifteen to twenty minutes after. A timer makes this automatic.

Transcript

Mould on your bathroom ceiling, even with the fan on? FreshDuct explains why. A fan that's running isn't always a fan that's extracting. If it dumps the moist air into the roof, or it's too weak for the room, the moisture stays. Run it during every shower and for fifteen to twenty minutes after. A timer makes it automatic. And make sure it actually vents outside. That's the first thing to check. No call-out fee, and you pay after the job.

Call FreshDuct on 04 3191 8137.