Cooker Hood Grease Filters: Metal Mesh, Baffle and How Often to Clean Them

A grease-saturated cooker hood filter is one of the most common causes of kitchen fires. The filter is the first component cooking vapours reach on the way into the hood, and it does exactly the job its name suggests: it catches fat, grease, and oil droplets before they enter the duct or the recirculating path. Most homeowners never think about it until the hood stops pulling steam, or until a flare-up on the hob finds it. When that mesh is saturated with grease, it stops being a safety device and becomes a fuel source, positioned directly above an open flame. This page explains what the filter does, the difference between mesh and baffle designs, how often to clean it, and what to buy when it finally needs replacing.

What a grease filter does

Cooking over a hob produces aerosols: tiny oil droplets suspended in moving air. Those droplets carry the smell and the residue you can see building up on tiles and cabinet doors near a hob that has no extraction. The grease filter intercepts them before they go any further.

It works by forcing the airflow to change direction sharply. A grease filter is a series of fine metal mesh layers, typically aluminium or stainless steel, that create turbulence as air is pulled through. The droplet-laden air cannot follow a straight path; it has to weave through the mesh. The droplets, being heavier than the air carrying them, cannot turn fast enough. They collide with the mesh surfaces, coalesce into larger drops, and either drip into a collection channel or are held in place by surface tension until you clean them off.

The cleaned air then passes through to the fan, in a ducted extraction system, or to the carbon filter, in a recirculating one. Without a functional grease filter, oil and fat carry straight on into the duct or the carbon. In a ducted system, oil accumulating along the inside of the duct creates a fire pathway running through the wall or ceiling void. In a recirculating system, oil reaching the carbon filter dramatically shortens the carbon's lifespan, because the carbon is meant to absorb odours, not soak up fat.

Metal mesh versus baffle

Two designs dominate the market, and the choice depends mostly on how hard you cook.

Metal mesh filters are made from multiple fine layers of corrugated aluminium or stainless steel mesh stacked together. They are the standard fitment on mid-range and budget hoods. They are light, cheap to replace, and usually dishwasher-safe. The one caveat in the dishwasher is to avoid loading them in the top rack hard against plastic items, as the filter can rattle loose during the cycle and get knocked out of shape.

Baffle filters take a different approach. Instead of mesh, they use a series of angled metal channels, the baffles, that force air through a sequence of tight 90-degree turns. Fat particles cannot follow the bends and collect on the baffle surfaces, draining down into a channel at the base. Baffle filters capture grease more effectively than flat mesh, which is why they are standard on commercial kitchen extraction and on premium domestic hoods from brands such as Neff, Bora, and Falmec. They are heavier and more expensive, and commercial-grade versions are dishwasher-safe across the board.

For most domestic kitchens, mesh filters are perfectly adequate. For high-output cooking, daily frying, wok burners, or commercial-style hobs rated over 5kW, baffle filters earn their premium through better capture and a longer service life.

The fire risk from a saturated filter

This is the part most people underestimate. A grease-saturated filter is a genuine fire risk, not a theoretical one. A flare-up on the hob, burning the base of a pan, or a gas burner catching dribbled oil, can ignite a heavily loaded filter. Once that mesh is alight, it turns a small contained flame into a structural fire inside the body of the hood, with the duct or the carbon filter directly behind it.

There is a second, slower problem too. A clogged filter strangles airflow. Grease blocks the mesh voids, the fan has to work against a restriction, and extraction capacity drops sharply. The result is more condensation on your ceiling and windows, lingering cooking odours, and damp settling into a kitchen that should be staying dry.

UK Fire Service guidance and the manufacturer instructions on virtually every cooker hood specify a maximum cleaning interval for exactly these reasons.

Warning

Never operate a cooker hood with a visibly saturated or discoloured grease filter. A heavily loaded mesh filter is a direct fire risk positioned directly above an open flame or electric ring. Clean or replace it immediately.

How often to clean it

UK manufacturer guidance generally sets the interval by how heavily you use the hob:

Light use (occasional cooking, a few times a week): clean monthly.
Normal daily cooking: clean every two to four weeks.
Heavy frying or grilling: clean every one to two weeks.

The most reliable indicator is the colour of the mesh. A clean filter is bright silver or grey. As grease accumulates, the mesh darkens. Next you see pooled fat sitting in the mesh voids, then the surface shifts to a yellow-brown. By the time it reaches that brown stage, it needs cleaning straight away. You should not wait for a scheduled date if the colour has already turned.

Tip

Set a recurring phone reminder to check the filter weekly until you learn how quickly your own cooking style loads it. Most households settle on a three to four week rhythm. If you fry in a pan most days, expect to clean more often than that.

Cleaning in the dishwasher

Most aluminium mesh and stainless steel baffle filters are dishwasher-safe, which makes routine cleaning simple. Run a normal hot cycle at 60 to 70°C, and try to keep the filter out of the path of direct high-pressure jets where you can, as repeated blasting can distort thin mesh over time.

What matters is what you do not use. Avoid harsh oven cleaners and abrasive pads on mesh filters. They strip the aluminium oxide layer that gives the metal its corrosion resistance, leaving you with white pitting that never comes off. Some hood manufacturers sell dedicated cooker hood degreaser tablets for dishwasher use, which are formulated to be safe on the mesh.

If you would rather not put it in with your crockery, soak the filter in hot water with a scoop of washing soda (sodium carbonate) for 20 to 30 minutes, then rinse thoroughly. This lifts grease effectively and carries no risk to the mesh structure.

When to replace rather than clean

Metal mesh filters tolerate many cleaning cycles, but they do not last forever. Replace the filter when:

The mesh is visibly deformed, buckled, bent, or with individual mesh wires that have failed and started to fray.
Dark discolouration refuses to lift after several dishwasher cycles, which means carbon deposits have bonded into the mesh and will not release.
The mounting clips or handle tabs are broken, so the filter no longer seats securely in the hood.

A securely seated filter matters more than it sounds. A filter that does not clip home properly lets unfiltered air bypass it, and on a ducted hood that means fat going straight into the duct.

Most mesh filters last three to five years with regular cleaning. Baffle filters, being heavier and more robust, often outlast the hood itself. Replacement mesh filters cost only a few pounds for generic cut-to-size material, rising to OEM (original equipment manufacturer) cassettes from premium brands at the top of the table below.

What to buy

Filter fit is brand-specific on most hoods, so check the model number printed inside the hood before ordering. The cassette clips on premium hoods are proprietary, and a universal panel will not always lock into them.

Type	Compatibility	Price approx	Notes
OEM aluminium mesh (Neff, Bosch, Siemens)	Model-specific	£10–25 each	Correct fit guaranteed. Buy via Bosch Parts, AO.com, or Espares.
OEM aluminium mesh (AEG, Electrolux)	Model-specific	£10–20 each	Available via Espares and 4OurHousehold. Quote the model number.
Universal cut-to-size mesh roll	Any hood, trim to fit	£5–12 per roll	Covers 3–5 filters. Cut with scissors. Less robust than a moulded cassette but effective. Amazon, CDA Appliances.
Stainless steel baffle replacement	Manufacturer-specific	£25–60 each	Longer-lived than mesh. Via Neff Trade, Elica, and Falmec parts services.

For premium hoods from Neff, Siemens, and AEG, buy the manufacturer-specific filter. The proprietary clips mean a universal panel rarely seats properly. For budget hoods such as Beko, Cookology, and supermarket own-brand units, a universal cut-to-size mesh roll is often the only replacement option you will find, and it works perfectly well once trimmed to size.

External resource

Espares cooker hood filter finder

Search by appliance brand and model number to find the correct OEM grease and carbon filters. Useful for confirming the right part before buying a generic alternative.

espares.co.uk

Common mistakes

The most frequent error is cleaning the filter in the dishwasher loaded alongside plates and glasses, where other items collide with the mesh during the cycle and bend it out of shape. Load it where nothing can knock it. The second is reaching for caustic oven cleaner on an aluminium mesh filter, which causes the white oxidation pitting that ruins the metal permanently. Third is the homeowner who never cleans the filter at all because the hood "seems to work fine", right up until it does not. Finally, on recirculating hoods, people replace the carbon filter but never check the grease filter at the same time. Both should be inspected together, since a saturated grease filter is what kills the carbon early in the first place.

Where you'll need this

Extractor and ventilation, where you choose the hood and decide ducted versus recirculating
Kitchen installation, where the hood is fitted and the filters first go in