Cooking Fires Start Where Grease Collects
The U.S. Fire Administration names cooking as the leading cause of home fires. In 2021, residential building cooking fires numbered about 170,000 and caused 135 deaths and 3,000 injuries, and unattended cooking equipment was a factor in 37 percent. A clean hood doesn't replace watching the stove, but grease in filters and ducts gives a pan fire more to reach.
Degreasing Metal Hood Filters at the Sink
Turn Off the Hood and Let It Cool
Filters come out through clips or a slide.
Soak in Hot, Soapy Water
Use a degreasing dish soap and let the filters sit.
Scrub Gently
A soft brush works the grease out of the mesh or baffles.
Rinse and Dry Completely
Reinstall only when dry.
Wipe the Hood Interior
Clean the grease film above the filters while they're out.
Check your hood's manual first; some metal filters are dishwasher-safe. Charcoal filters in ductless, recirculating hoods get replaced, not washed.
Where a Kitchen Hood Duct Must Go
| Rule | Section |
|---|---|
| Vents outdoors, never into an attic or crawl space | M1503.3 |
| Smooth-interior, airtight duct with a backdraft damper | M1503.3 |
| Independent of other exhaust systems | M1503.3 |
| Listed ductless hoods are an exception | M1503.3 |
| Makeup air for hoods rated above 400 cfm | M1503.6 |
A hood that vents into the attic leaves grease on insulation and framing; the attic ductwork page covers the other exhausts with the same rule.
When the Duct Needs a Professional
- Grease drips from the hood or collects around the fan
- The hood is loud but moves little air, even with clean filters
- The outdoor damper sticks with grease
- You're unsure whether the hood vents outdoors at all
A technician degreases the fan and duct, checks the damper and termination, and confirms where the duct actually ends.
Airflow Minimums and Makeup Air
Section M1505.4.4 sets the minimum kitchen exhaust rate at 100 cfm for a fan run intermittently, or 25 cfm for continuous operation. Large hoods pull the other way: above 400 cfm, the code requires makeup air to replace what the hood removes. The full set of household exhaust rates is on the whole-home ventilation page.
How Range Hood Duct Cleaning Is Priced
Nobody can give a fair price for a greasy duct over the phone, which is why honest companies quote after looking. What you can know in advance is what moves the number.
| Factor | Lower cost | Higher cost |
|---|---|---|
| Duct route | Short run straight through an exterior wall | Long run through a ceiling to the roof |
| Grease load | Film you can wipe | Built-up grease that has to be scraped |
| Hood type | Wall-mount hood with reachable fan | Island hood or inline fan in the ceiling |
| Termination | Wall cap at ground level | Roof cap needing a ladder |
Filter cleaning stays your job and costs nothing. The paid work starts where your hand stops reaching: the fan housing, the duct, the damper and the cap.
Angi's 2026 cost data puts professional cleaning of a single standard residential hood at $200 to $400, and an island or custom hood at $350 to $700. Hard-to-reach setups, such as high ceilings or a roof termination, add $100 to $400. A quote far under $200 for the full system usually covers the filters and hood face, not the duct.
Source: Angi, How Much Does Kitchen Hood Cleaning Cost? (updated May 3, 2026). U.S. national ranges, not a quote.