How often should you clean the range hood filter?

Short answer

Clean the range hood filter every 1 to 3 months. If you fry a lot, every month. The filter is the metal mesh panel on the underside of the hood, and it catches the grease in cooking smoke before the fan pulls the air outside or back into the kitchen. A soak in hot, soapy water takes 15 to 30 minutes and costs $0 to $20, the higher end being a replacement charcoal filter for a hood that doesn't vent outside.

Why it matters

Cooking puts grease into the air as a fine mist. The hood's mesh filter is a maze of thin metal that the air has to weave through, and the grease sticks to the metal while the air goes on. That's the whole design, and it works until the mesh is coated. Then the fan pulls less air, smoke lingers over the stove, and the grease the filter can't catch goes up into the fan and the duct instead.

Grease in a fan and duct is a fire hazard. A pan that flares up under a clogged hood has a trail of fuel leading up into the wall. It's also a mess that spreads: grease drips back out of a saturated filter onto the stove, and a film settles on the cabinets around the hood. A filter that's washed on schedule keeps the grease in the one place that's easy to clean.

When to do it more often

Lots of frying, searing or wok cooking: every month. High heat throws far more grease into the air than simmering does.
A ductless hood, which pushes air through a charcoal filter and back into the kitchen: replace the charcoal filter every 3 to 6 months, since it can't be washed and stops trapping odors once it's full.
A big household cooking every day: lean toward the monthly end whatever the style of cooking.

What you need

A sink or basin big enough to lay the filter flat
A soft brush for the mesh
Degreasing dish soap
Baking soda, for a filter that's badly coated
A replacement charcoal filter, for a ductless hood

Steps at a glance

Slide or unclip the mesh filter from the underside of the hood.
Fill the sink with the hottest tap water, a good squirt of degreasing dish soap, and a handful of baking soda.
Submerge the filter and let it soak until the grease loosens.
Scrub the mesh gently with the brush, rinse with hot water, and look through it toward a light to check it's clear.
Dry it fully, wipe the grease off the hood's underside while the filter is out, and slide it back in.
On a ductless hood, swap the charcoal filter behind the mesh when it's due.

You're done when light shows evenly through the whole mesh and the fan pulls a sheet of paper towel up against the filter.

Signs it's overdue

Grease dripping from the hood onto the stove.
A filter that's sticky to the touch or visibly coated.
Weak suction, with smoke rolling out from under the hood instead of up into it.
Smoke or cooking smells that linger long after the stove is off.

DIY or pro

This is an easy job, and it's mostly soaking. Hot water and degreasing soap do nearly all the work, and the baking soda handles a filter that's been neglected for a year. Some mesh filters go through the dishwasher, but the strong detergent can discolor aluminum, so check the manual before trying it.

There's no routine service to hire. A hood cleaning company exists for restaurant kitchens, not home ones. A technician's visit is for a fan that's noisy or weak after the filter is clean, which means grease has reached the fan itself or the duct above it.

FAQ

Can you put a range hood filter in the dishwasher?

Some, if the manual allows it. Dishwasher detergent can dull or discolor aluminum mesh, so a soak in the sink is the safer choice for most filters.

How do I know if my range hood filter is dirty?

Hold it up to a light. If light doesn't show through the mesh evenly, or the filter feels sticky, it needs cleaning.

What is the charcoal filter in a range hood for?

On a hood that doesn't vent outside, it absorbs cooking odors before the air goes back into the kitchen. It can't be cleaned and is replaced every 3 to 6 months.

Does a range hood need to vent outside?

It works best that way, since the grease and moisture leave the house. A ductless hood catches grease and some odor but returns the heat and humidity to the room.