The extractor is the most ignored appliance in a British kitchen and the one with the clearest safety case for cleaning. Grease-loaded filters are the main fuel source in kitchen fires, and a saturated filter stops extracting long before it looks dirty. This guide explains the two system types, how to tell which one you have, and what good cooker hood cleaning involves.
Ducted or recirculating: find out first
Everything else follows from this.
- Ducted hoods push air outside through a rigid or flexible duct. They have metal grease filters only, and they need the duct run checked as well as the filters.
- Recirculating hoods pull air through a grease filter, then a carbon cartridge, and blow it back into the room. Carbon is a consumable: it cannot be washed, and once it is spent the hood moves air without removing smell.
The quick test: run the hood on full and hold a sheet of kitchen paper to the outlet grille above the unit. If air is coming back at you, it recirculates. Most flats, most island hoods and almost every kitchen fitted into an internal wall recirculate.
Filter types and how they are cleaned
| Filter | Found on | Method | Interval |
|---|---|---|---|
| Mesh (aluminium layers) | Most domestic hoods | Degrease and soak, rinse, dry flat | Every 1–2 months |
| Baffle (stainless slats) | Professional-style and island hoods | Tank soak, brush between slats | Every 1–3 months |
| Carbon cartridge | Recirculating hoods only | Replace — never wash | Every 4–6 months |
| Downdraft cassette | Hob-integrated extraction | Remove cassette, degrease, clear sump | Every 2–3 months |
Washing a carbon cartridge is the single most common mistake. Water collapses the granule structure; the cartridge comes out looking clean and no longer adsorbs anything.
What a professional visit covers
- Filters out and tanked — degreased properly rather than run through a dishwasher, which dulls aluminium and rarely clears baffle slots.
- Canopy and plenum — the chamber above the filter, where grease actually accumulates, hand-cleaned.
- Impeller and motor housing — degreased where accessible; a greased impeller loses a surprising amount of airflow.
- Duct run inspected — first accessible metre cleaned, damaged or crushed flexible ducting flagged.
- Carbon replaced — if recirculating and due, with the model noted for next time.
- Airflow check — before and after, so the improvement is demonstrable rather than asserted.
Expect £30–£70 as an add-on to another appliance job, or £60–£120 as a standalone visit depending on hood type and access. Booking it alongside an oven clean is materially cheaper — see the oven cleaning cost guide for combined pricing.
The fire and compliance case
Grease deposits are the fuel in the overwhelming majority of kitchen extraction fires. In a domestic kitchen this is a housekeeping matter; in a let property or a commercial kitchen it is an insurance one. Landlords and HMO operators are routinely asked to evidence extraction maintenance, and a dated invoice with before-and-after photographs is what satisfies that request. If you run a commercial kitchen, extraction cleaning falls under a different standard entirely and should be scheduled with commercial cleaning.
Keeping it clean between visits
- Run the hood for three to five minutes after you finish cooking — extraction is about clearing the residual plume, not the peak.
- Start it before you heat the pan, on the lowest useful speed.
- Wipe the canopy underside weekly while it is still warm; cold grease is a different job.
- Diarise carbon replacement. Six months is realistic for a household that cooks most nights.
Five signs yours is overdue
Smells lingering into the next morning. Condensation on the wall cupboards beside the hob. A filter that no longer springs back or drips when tilted. Rising noise at the same speed setting. A visible grease line on the ceiling above the hood. Any two of those together and the filters are past saturation.
Book extraction cleaning as part of appliance cleaning, or add it to a deep clean if the whole kitchen needs resetting. Not sure which you need? Our deep clean vs regular clean guide covers the difference.