Why does my bathroom stay humid even with the fan on?
Bathroom fans often make plenty of noise while failing to move air, leading people to spend months wiping condensation off walls while assuming the unit is broken. The actual problem is that the grille and fan blades accumulate buildup that blocks airflow, leaving bathrooms humid forever after showers until those hidden parts are thoroughly cleaned.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
Found another way around this?
Share your steps and trade-offs so fellow engineers don't have to reinvent the wheel. No account required.
- 1Wiping condensation off walls and mirrors manuallyDid this help you?
- 2Performing the tissue test to check suctionDid this help you?
- 3Removing the cover and vacuuming or washing internal fan blades and grillesDid this help you?
- 4Run a small dehumidifier during and after showersDid this help you?
- 5Leave the bathroom door cracked open and use a fan pointing toward the hallwayDid this help you?
- 6Replacing flexible vinyl tubing with rigid metal ductingDid this help you?
- 7Rotating the fan housing 180 degrees to eliminate bends and create a straight runDid this help you?
- 8Blowing out the duct tube with a leaf blowerDid this help you?
- 9Bathing with the bathroom door open and letting the fan run longer after showeringDid this help you?
- 10cleaning and getting rid of the mold temporarilyDid this help you?
In their words
Unedited, grouped by where they were said, most upvoted first within each place, each linked to the thread it came from.
“My bathroom always stayed humid forever after showers.”source ↗
“The fan made noise, so I assumed it was working.”source ↗
“Mine immediately fell on the floor.”source ↗
“I've spent months wiping condensation off walls and blaming the fan when apparently I had never actually cleaned the part of the fan that mattered.”source ↗
“Mine was technically running for years, meaning it successfully converted electricity into noise. Cleaned the grille and fan blades and suddenly it could actually hold a square of toilet paper.”source ↗
“We just bought our first house and have a Homewerks 110 CFM brand bathroom exhaust fan (Model #7130-13-BT) that is barely pulling steam/air during shower.”source ↗
“The bathroom gets very steamy during use and the fan barely sucks in a single piece of toilet tissue when on.”source ↗
“Ran the fan with vinyl tubing attached to the fan and disconnected from the soffit and there was very poor suction.”source ↗
“I'm looking for a temporary solution to our mold problem.”source ↗
“because this tiny bathroom doesn't have any sort of ventilation we have black mold growing everywhere.”source ↗
“I was just wondering if there's a way to prevent it from coming back or at least slow the progression until we can get proper ventilation installed?”source ↗
Where this came up
People with this problem also raised
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- 13Why is my AC air handler wet and smelly?
- 3Roof vents installed off-center and poorly aligned
- 25Why is one bedroom getting way more air than other rooms?
- 2Why does my bathroom mirror still fog up when the exhaust fan is running?