TL;DR
Metal mesh grease filters are washable and last for years; charcoal filters are consumable and must be replaced every three to six months in typical use. Washing a charcoal filter destroys it, and replacing a metal one that only needs a degreasing wastes money. Almost every hood has a metal grease filter, and only recirculating hoods add a charcoal one behind it.
Which filter do I have?
Look at the panel. A metal grease filter is a rigid rectangle of aluminum or stainless mesh, or a baffle panel of angled metal plates, and it clips into the underside of the hood. A charcoal filter is a lighter black or gray pad or cassette that sits above or behind the metal filter, and it is only present if the hood recirculates air back into the room instead of venting outside.
What each one actually does
The grease filter catches airborne cooking oil. Vapor hits the cold metal, condenses, and drains or clings. That is a purely mechanical job, which is why washing restores it completely.
The charcoal filter adsorbs odor molecules onto activated carbon. That is a chemistry job with a finite capacity. When the surface sites are full, the filter stops working, and there is no way to empty them out at home.
That difference is the whole article. One is a strainer you can rinse, the other is a sponge that fills up permanently.
Ducted vs recirculating, and why it matters
A ducted hood vents to the outside. It only needs a grease filter, because the odor and moisture leave the building. If your hood vents outdoors, there is no charcoal filter to buy.
A recirculating hood filters air and blows it back into the kitchen. It needs both: grease filter first, then charcoal for odor. It also removes far less moisture and heat than a ducted hood, which is worth knowing when a kitchen feels steamy no matter what. Does a range hood improve indoor air quality covers what each configuration realistically achieves.
If you are not sure which you have, check whether there is a duct running up through the cabinet or out the wall behind the hood.
How often to clean a metal grease filter
Every one to three months for typical home cooking, and monthly if you fry, wok cook, or cook with oil most nights.
The practical test is airflow and drip. When the hood gets noticeably louder and less effective, or when grease starts beading on the underside of the hood, the filter is saturated. Why my range hood drips grease covers what that dripping is telling you.
A saturated grease filter is also a fire consideration. A loaded filter directly above a burner is a concentration of flammable residue, which is the main reason manufacturers publish cleaning intervals at all.
Washing a metal filter
Dishwasher: most stainless and baffle filters go on the top rack, and many aluminum mesh filters do too. The caution is that hot alkaline dishwasher detergent darkens and dulls bare aluminum over time. It is cosmetic rather than functional, but it surprises people the first time.
Hand soak: fill a sink with the hottest tap water you can manage, add a strong squirt of grease-cutting dish soap and a few tablespoons of baking soda, and let the filter sit for fifteen to thirty minutes. Scrub with a soft brush, working with the mesh rather than across it, then rinse thoroughly and dry completely before reinstalling.
What to avoid: lye-based oven cleaner on aluminum, which reacts with the metal and pits it. Chlorine bleach, which does nothing useful on grease and pits stainless. And never combine chlorine bleach with ammonia, with any acid including vinegar, or with rubbing alcohol.
How to clean range hood filters walks through the full method, and how often to clean a range hood filter covers setting the interval to your cooking.
When a metal filter is genuinely done
Metal filters commonly last five to ten years or longer, and many outlive the hood. Replace one when the mesh is torn or crushed, when a baffle is bent enough that it no longer seats, when the frame has corroded through, or when the handle has broken off and the filter cannot be secured.
Persistent stickiness after a proper hot degreasing soak usually means the soak was not hot enough rather than that the filter is finished. Try once more with hotter water before buying.
Replacement metal filters are inexpensive, and stock sizes cover many hoods.
When to replace a charcoal filter
Every three to six months in typical home use, and closer to three with heavy cooking. Some manufacturers rate theirs by hours of operation instead.
The signal is odor. When cooking smells linger in the kitchen the way they did before you ran the hood, the carbon is spent. There is no visual cue, which is why people forget these entirely.
Charcoal filters cannot be washed, baked, or regenerated. Washing floods the pore structure and ends the filter's useful life immediately. Advice to bake a carbon filter to refresh it comes from industrial regeneration processes that use temperatures and controlled conditions no home oven provides.
Replacement charcoal filters are a recurring cost, sometimes sold in pairs.
The decision in one line each
Metal grease filter: clean it, every one to three months, and only replace it when it is physically damaged.
Charcoal filter: replace it, every three to six months, and never try to clean it.
Both present: clean the metal one on its schedule and replace the charcoal one on its own. They are independent.
What happens if you skip it
Airflow drops first. A loaded filter chokes the fan, so the hood gets louder and captures less, and grease that would have been caught starts landing on cabinets, walls, and the ceiling instead.
Then the hood itself gets greasy inside, including the fan housing and the duct, which is a much harder cleaning job than a filter soak.
Then odor and moisture stay in the room. In a recirculating setup a spent charcoal filter means the hood is doing almost nothing about smell.
And the fire risk rises, because saturated grease sits directly above open flame. Keeping the filter on schedule is genuinely the cheapest safety measure in the kitchen, and it fits neatly into a monthly routine alongside the rest of kitchen cleaning from wipe downs to deep cleans.
FAQ
Can you wash a range hood charcoal filter?
No. Activated carbon works by adsorbing odor molecules onto its internal surface, and washing floods that structure without releasing what is already held. A washed charcoal filter is finished. Replace it every three to six months in typical use.
How often should you replace a range hood filter?
Metal grease filters are washed every one to three months and only replaced when physically damaged, often after five to ten years. Charcoal filters in recirculating hoods are replaced every three to six months because they cannot be cleaned.
Can range hood filters go in the dishwasher?
Most stainless and baffle filters can, on the top rack. Aluminum mesh filters usually can too, but hot alkaline detergent gradually darkens and dulls bare aluminum. That change is cosmetic and does not affect how well the filter works.
How do I know if my hood has a charcoal filter?
Only recirculating hoods use one. If your hood vents outdoors through a duct, there is no charcoal filter. If the air blows back into the kitchen, look for a lighter black or gray pad or cassette sitting above or behind the metal grease filter.
What is the best way to degrease a metal filter?
A hot soak. Very hot water, a strong squirt of grease-cutting dish soap, and a few tablespoons of baking soda for fifteen to thirty minutes, then a soft brush and a thorough rinse. Avoid lye-based oven cleaner on aluminum, which pits the metal.
Why is my range hood dripping grease onto the stove?
Because the filter is saturated and grease is condensing on the hood body instead of draining through. Clean the filter, and check the interior of the hood and the fan housing, which usually need degreasing at the same time.
Does a dirty filter make the hood louder?
Yes. A loaded filter restricts airflow, so the fan works harder against the restriction and the sound changes noticeably. A hood that has grown louder and less effective over months is usually telling you the filter is due rather than failing.
Filters are the cheapest maintenance in the kitchen and the easiest to forget. If the grease has already spread to the cabinets and walls, our house cleaning crews are local and background-checked, with upfront pricing and no hidden fees. Every home is different, so the real number depends on size, condition, and what you want covered. Get a quote and we will walk you through it.
