Canopy, filters & fan
A mesh filter is the cheapest, lightest option in the canopy, and that is most of its appeal. But it traps grease in the body of the wire rather than draining it, so it clogs quickly, needs washing far more often than a baffle, and can carry flame - which is why current guidance keeps mesh to a secondary role at best.
The short answer
A mesh filter is the cheapest, lightest option in the canopy, and that is most of its appeal. But it traps grease in the body of the wire rather than draining it, so it clogs quickly, needs washing far more often than a baffle, and can carry flame - which is why current guidance keeps mesh to a secondary role at best.
The detail
A mesh filter is built from several layers of fine aluminium or steel wire. Grease-laden air passes through and droplets snag in the tangle of the mesh, held in place rather than run off. That gives it a lower airflow resistance than a baffle when clean - around a third as much - and makes it cheap and light to buy, which is why older kitchens are full of them.
The trouble is that held grease does not drain. It accumulates in the wire layers until the gaps close, and a clogged mesh chokes airflow far sooner than a baffle would. Because it blinds so quickly, mesh needs washing every week or two in a working kitchen rather than being left to a routine soak, and the fine wires trap grease in places a wash struggles to reach.
Grease sitting in the mesh is also a fire concern. A baffle throws grease into a drained channel away from the airstream; a mesh holds it in the very path the air and any flame would travel, so a build-up in the wire can act as a medium that carries fire rather than resisting it. This is the core reason baffles displaced mesh as the primary filter in modern specifications.
Mesh also wears out. The thin wires corrode, flatten and tear with repeated washing, and once deformed the filter no longer seats or filters properly. Where a stainless baffle lasts for years, a mesh filter is a consumable that needs honest budgeting for replacement, not just cleaning - a cost that erodes its low purchase price over time.
What it means for you
If your canopy still runs mesh as a primary filter, the safe response is frequency and vigilance: wash often, before it clogs rather than after, and replace filters the moment the wires deform or corrode. A clogged or damaged mesh is worse than no filter, because it starves the fan while still letting grease through into the duct.
Switching to baffles is often worth it, but it is not a like-for-like swap. Baffles resist airflow far more than mesh, so dropping them into a canopy sized for mesh can cut extraction and even overload the fan. A change of primary filter should be checked against the canopy and fan design, or the kitchen ends up hot, smoky and no safer.
Whatever filter you run, the point is the same: grease not stopped at the filter has to be removed from the plenum, duct and fan instead, at far greater cost and disruption. Mesh can do a job as a secondary stage or in a light-use kitchen, but as a neglected primary in a busy one it quietly loads the whole system with the grease it was meant to catch.
The service behind the guide
Sibling guides
Cartridge and HEPA stages · How often to clean baffle filters · Your compliance certificate
Questions
They are cheap, light and low-resistance when clean, which suits light-use kitchens or a secondary stage. As a primary filter in a busy kitchen they clog fast and can carry flame, so baffles are preferred.
Far more often than baffles - typically every week or two in a working kitchen - because they hold grease in the wire and clog quickly rather than draining it away.
Grease held in the mesh sits in the airstream, where it can act as a medium that carries flame rather than resisting it. Baffles throw grease into a drained channel away from the air path.
Yes, but not like for like. Baffles resist airflow much more than mesh, so the change should be checked against the canopy and fan design or extraction can drop and the fan can be overloaded.
Yes. The fine wires corrode, flatten and tear with repeated washing. Once deformed they no longer filter properly and must be replaced, so mesh is a consumable rather than a durable filter.
Phoenix Duct Clean · by the numbers
We clean the whole path - canopy, filters, plenum, ductwork and fan - and verify the result to TR19 Grease. Call or email for a clear quote and a certificate you can show your insurer.