A bathroom or kitchen exhaust fan rarely fails; it slows down. Dust packs the blades, grease coats the grille, and the airflow drops until the mirror stays fogged and the mould starts in the corner above the shower.
Dust on the blades, grease on the grille
A bathroom exhaust fan loses performance from dust on the blades and grease on the grille. Isolate the power, remove the cover, wash it in warm water with a degreaser, and vacuum the blades; the duct behind it matters more than the fan itself. A rattling fan is usually a loose blade.
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The safe order of work
- Isolate the power at the switch or the breaker. A fan that switches on while your hand is inside it is the main safety risk in this job.
- Remove the cover or grille. Most bathroom units have a spring clip or two screws; kitchen canopy filters lift out.
- Wash the cover in warm water with a degreaser. A bathroom fan cover is mostly dust, a kitchen one is grease, and the same product handles both at different dilutions.
- Vacuum the blades and housing with a brush attachment. Do not bend the blades; an unbalanced blade is the rattle you will hear afterwards.
- Wipe the surrounding surface and refit. Check the fan runs freely before you screw the cover back on.
Products and tools that make it quick
| Item | Use | Price |
|---|---|---|
| Heavy Duty Degreaser 395 | Soaking kitchen grilles and canopy filters | A$60.00 |
| Quick Break Solvent Degreaser 426 | Carbonised grease on kitchen fans and ducting | A$74.00 |
| Agar HF Detergent | Heavy-duty detergent degreaser, 5 L | A$39.00 |
| 32 mm telescopic vacuum rod | Reaching fan housings and ceiling vents | A$26.50 |
| Cobweb brush with telescopic handle | Dusting around ceiling vents before vacuuming | A$20.00 |
Cleaning without removing the fan
Where the unit is hard-wired or you are not comfortable removing it, you can still make a real improvement: isolate the power, remove the cover, vacuum what you can reach, then wipe the visible blades with a cloth dampened with degreaser. What you cannot do this way is clean the duct, which is where the airflow restriction usually is.
When the duct is the problem
If the fan is clean and the room still stays steamy, the fault is downstream: a crushed, disconnected or grease-filled duct, or a roof vent that has been blocked. Kitchen ducts in particular accumulate grease on the inside walls, and that is both an airflow problem and a fire risk, which is why commercial kitchen ductwork has a scheduled clean. In a home or small premises, the test is simple: with the fan running, hold a sheet of toilet paper against the grille. If it will not hold, the airflow is inadequate.
Ventilation, mould and the reason it matters
An exhaust fan exists to remove moisture, so a fan that has lost half its airflow is a mould problem waiting to happen. Cleaning it is the cheapest mould prevention available: dust and grease are the only reasons a working fan stops working.
On commercial premises, the duct clean and the fire risk are documented obligations, and SafeWork NSW covers the equipment and chemical handling side in machinery and equipment and chemicals and other substances.
Bathroom fans and kitchen canopy fans are different jobs
A bathroom fan mainly moves moisture and collects dust plus lint. A kitchen canopy fan moves hot, greasy air and collects a layer that becomes sticky and then hard. The cleaning products overlap, but the method does not: bathroom covers can be dusted and washed with a neutral cleaner, while kitchen filters need an alkaline soak and, where the grease has carbonised, a solvent degreaser.
Commercial kitchen exhaust systems carry a compliance dimension that bathroom fans do not. Grease in a duct is a fire load, and the clean is a scheduled, documented task. SafeWork NSW covers the equipment side under machinery and equipment, and Food Standards Australia New Zealand covers ventilation and cleaning expectations for food premises.
Questions we get asked most
- What is the best way to clean a bathroom exhaust fan?
- Isolate the power, remove the cover, wash the cover in warm water with a degreaser, and vacuum the blades and housing. Refit only after checking the fan spins freely.
- How to clean dust out of an exhaust fan?
- A vacuum with a brush attachment does most of it, with a damp cloth for the blades. Never bend the blades, and do not use water inside the motor housing.
- How to clean an exhaust fan without removing it?
- Remove the cover if you can, isolate the power, and vacuum and wipe what is reachable. That restores some airflow, but the duct and the far side of the blades need the unit out.
- Why does my exhaust fan rattle?
- Usually a loose blade, a bent blade, or a cover that has not seated on its clips. Check the cover first, then the blade balance.
- How often should a kitchen exhaust fan be cleaned?
- Domestically, every few months. In a commercial kitchen the canopy filters are cleaned weekly at minimum and the ductwork is on a scheduled professional clean, because grease in a duct is a fire risk.
References
Kitchen canopy on a schedule?
Tell us how many hoods and filters you have, and we will set up the soak routine and the dilution that keeps the airflow where it should be. Browse degreasers or ask our team.