TL;DR
Kill the power at the breaker before anything else, then work in two categories: parts that come out get soaked in hot degreaser, and parts that stay in get wiped with a cloth. The motor is the line you do not cross, since it is never sprayed, never soaked, and never wetted. Plan on sixty to ninety minutes for a hood that has not been touched in years.
Why a fan gets this bad
A kitchen exhaust fan pulls greasy air through itself continuously, which means every blade surface is coated in cooking oil that has polymerized into a hard varnish, the process described in why kitchen grease is so stubborn.
That coating adds weight and roughness to the blades, so the fan moves less air, makes more noise, and lets more grease escape into the room, which is why cabinets and walls get worse once the fan is neglected.
Power off first, and prove it
Switch the breaker off, not just the wall switch or the hood control. Then turn the fan control on and confirm nothing happens.
Fan assemblies have sharp sheet metal edges and there is often a light socket in the same housing, so this is not a step to shortcut. Wear gloves and eye protection, since you will be working overhead with degreaser.
Take it apart
- Put a drop cloth or old towels on the cooktop and counter below.
- Remove the metal grease filters, which release with a small tab or spring clip.
- Remove the light cover and bulbs if the housing has them, so nothing gets splashed.
- Look for the fan assembly. Many hoods have a squirrel cage blower held by a couple of screws or a wing nut; some have a simple bladed fan on the motor shaft.
- Photograph the assembly before removing anything, so reassembly is not guesswork.
- Remove the blower wheel or blade assembly if it detaches. If it is fixed to the motor, leave it in place and clean it in position.
- On ductless recirculating hoods, locate the charcoal filter and replace it. It is never washed.
Soak what comes out
Fill a sink or a deep tote with the hottest water you can safely handle, add a strong squeeze of degreasing dish soap and a quarter cup of washing soda or baking soda per gallon, and submerge the filters and the blower wheel.
Give it twenty to thirty minutes, then scrub with a nylon brush. Squirrel cage blowers have dozens of small vanes, so a narrow bottle brush or an old toothbrush earns its place. Rinse thoroughly with hot water and dry completely before reinstalling. The same soak details apply to degreasing range hood filters.
Never add chlorine bleach to that soak, and never combine bleach with vinegar, a descaler, or an ammonia based cleaner anywhere in the kitchen.
Wipe what stays in
The housing interior, the canopy underside, and the fan mounting plate all get wiped rather than sprayed. Apply degreaser to a cloth, hold it against the greasy area for a minute, then wipe. Repeat rather than pressing harder.
| Part | Method |
|---|---|
| Metal grease filters | Soak and scrub |
| Blower wheel or fan blades | Soak if removable, wipe if not |
| Motor and wiring | Wipe the exterior lightly, keep dry |
| Housing interior | Degreaser on a cloth, dwell, wipe |
| Light socket area | Dry cloth only |
| Charcoal filter, ductless models | Replace, never wash |
| Duct opening and damper flap | Wipe reachable areas, check it swings freely |
The motor rule is absolute. Liquid in the motor windings or the bearings ruins it, and a replacement motor usually costs more than a new hood on lower priced models.
The damper nobody checks
Look up into the duct opening for a flap that swings open when the fan runs. Grease can glue it shut, which means the fan pulls against a closed door and moves almost no air at all.
Wipe it and confirm it swings freely by hand. If the ductwork itself is heavily coated, that is a job for a professional hood or duct cleaning service rather than a household project, particularly on long runs or a rooftop termination.
Reassemble and set a schedule
Everything goes back dry, in the order your photos show. Restore power and run the fan on each speed to confirm smooth, quiet operation. A rattle usually means the blower wheel is not seated squarely.
Clean the filters monthly if you fry, quarterly otherwise. Do the fan and housing once or twice a year. Doing that consistently keeps grease out of the room, which is what prevents the sticky film on top of kitchen cabinets and grease on kitchen walls above the stove from ever building up. The order for the whole room is in the wider kitchen cleaning guide.
FAQ
How do I clean the fan blades in a range hood?
Cut power at the breaker, remove the filters, then remove the blower wheel if it detaches and soak it in very hot water with degreasing dish soap and washing soda for twenty to thirty minutes. Scrub with a narrow brush, rinse, and dry fully before reinstalling.
Can I spray degreaser directly into a range hood?
No. Spraying sends liquid into the motor, the wiring, and the light socket. Apply degreaser to a cloth instead, hold it against the greasy area for about a minute, then wipe. Repeat as needed rather than increasing the amount of liquid.
How often should a kitchen exhaust fan be cleaned?
Clean the metal filters monthly if you fry regularly and quarterly otherwise, and clean the fan assembly and housing once or twice a year. A fan that has become noisy or seems to pull less air is telling you it is overdue regardless of the schedule.
Why is my range hood so loud all of a sudden?
Grease buildup on the blower wheel adds weight unevenly and throws it out of balance, which causes vibration and noise. Cleaning the wheel usually fixes it. If noise persists after cleaning, the motor bearings may be worn and need service.
What if the fan does not seem to pull any air?
Check three things in order: whether the filters are clogged, whether the damper flap in the duct opening is stuck closed with grease, and whether the hood is a ductless model with an exhausted charcoal filter. All three are common and all three are fixable.
Do I need to hire someone to clean the ductwork?
For a short duct run, wiping what you can reach is usually enough. Long runs, rooftop terminations, and heavily coated ducts are a job for a professional hood cleaning service, since grease inside ductwork is a fire risk and is not reachable from the kitchen.
When the whole house is the problem rather than one task, recurring house cleaning services are the wider option.
Exhaust fans are the reason a kitchen either stays clean or slowly turns sticky everywhere. Every home is different, so what a full reset takes depends on size, condition, and what you want covered. Get a quote and we will walk you through it.