Grease filters sit in the canopy and catch some of the grease in cooking vapour before it reaches the duct. They’re the one part of the extract that kitchen staff can look after every day. Clean filters keep air moving, reduce the grease reaching the ductwork and help the extract fan last longer. Neglected filters do the opposite. This guide covers how to clean them, how often and what to do if the kitchen doesn’t have time.
Baffle filters vs mesh filters
Most commercial canopies use one of two types:
- Baffle filters are made from overlapping metal channels, often stainless steel. Air is forced to change direction several times, and grease is thrown out onto the baffles and drains into a channel or cup. They’re robust and easy to clean.
- Mesh filters are made from layers of metal mesh. They trap grease in the mesh itself. They clog more quickly and are harder to clean thoroughly, and damaged mesh lets grease straight through.
Whichever type you have, filters only catch part of the grease. Some always passes into the plenum and duct, which is why a full system clean is still needed.
How often to clean them
It depends on how much you cook and what you cook. As a rough guide:
- Heavy frying, grilling or wok cooking: daily, or every few days.
- A busy general kitchen: at least weekly.
- Light use: regularly enough that grease never builds up on the surface.
A simple test: if the filter looks dark and sticky, or if light won’t pass through the mesh, it’s overdue. Write it into the cleaning schedule, with a name against it.
How to clean filters safely
- Switch off the cooking equipment and let the canopy cool.
- Remove filters carefully, as they can be heavy and drip grease.
- Soak them in hot water with a suitable degreaser, following the product instructions.
- Scrub or rinse, then check that the grease has gone from inside the channels or mesh.
- Let them dry and refit them the right way round, seated properly with no gaps.
Some kitchens use a dishwasher or soak tank, if the filter maker allows it. Don’t run the extract without filters in place, even for a short time.
Need it done? Duct Doctor cleans and tests kitchen extract and ventilation systems across London and the South East, with a certificate and photo report after every clean. Get a fixed quote.
Signs a filter needs replacing
- Bent or crushed baffles that leave gaps.
- Torn or holed mesh.
- Filters that no longer fit the canopy snugly.
- Corrosion or damage that won’t clean off.
A gap around a filter lets grease bypass it completely and go straight into the duct.
Filter exchange services
If staff don’t have time to clean filters properly, an exchange service can help. Clean filters are swapped in on a schedule and the dirty set is taken away for cleaning. The kitchen always has clean filters and nobody is left soaking them at the end of a shift. Duct Doctor offers a grease filter exchange service alongside full kitchen extract cleaning.
Filters and the full clean
Even with spotless filters, grease still reaches the ductwork. BESA sets minimum cleaning intervals for the whole system by hours of use, from every 3 months for heavy use to every 12 months for light use (BESA). Good filter habits help keep grease readings down between those cleans. See how often to clean a kitchen extract.
Quick answers
Can I put grease filters in the dishwasher?
Some can go in a commercial dishwasher. Check the filter maker’s guidance first.
Should we run the extract without filters?
No. Without filters, grease goes straight into the duct and fan.
Are baffle filters better than mesh?
Baffle filters are generally easier to clean and harder to damage, which is why many kitchens prefer them.
Related services
More advice
- Signs Your Kitchen Extract Needs Cleaning
- How Often Should a Kitchen Extract Be Cleaned?
- Canopy-Only Cleaning vs a Full TR19 Clean
- Kitchen Extract Fires: How They Start and Spread
- All advice
This guide is general information. It isn’t legal or insurance advice: check your own policy wording and lease, and speak to a qualified adviser about your fire risk assessment.