Canopy, filters & fan
The grease filter in your canopy decides how it should be cleaned, how often, and how much grease reaches the rest of the system. Baffle, mesh and cartridge filters trap grease in different ways, so a method that suits one can be useless or damaging on another. Knowing which you have is the starting point.
The short answer
The grease filter in your canopy decides how it should be cleaned, how often, and how much grease reaches the rest of the system. Baffle, mesh and cartridge filters trap grease in different ways, so a method that suits one can be useless or damaging on another. Knowing which you have is the starting point.
The detail
A baffle filter is a set of interlocking steel vanes that force grease-laden air to change direction sharply. Heavy grease droplets cannot follow the turn, strike the vanes and run down into a collection channel, so the filter is largely self-draining. Baffle filters capture roughly 85 to 90 per cent of airborne grease, resist flame, and wash cleanly by soaking or in a utensil washer. DW/172 specifies them as the primary filter for exactly these reasons.
A mesh filter is layers of fine aluminium or steel wire that hold grease in the body of the mesh. It is lighter and cheaper, but it traps grease rather than draining it, so it clogs quickly and needs far more frequent cleaning. Grease held in the mesh can also act as a path for flame, which is why current guidance treats mesh as a secondary filter behind a baffle rather than a primary on its own.
Cartridge and secondary-stage filters sit further along - honeycomb cells, coil filters ahead of UV, or fine media that catches what the primary misses. They hold grease deep in their structure, cannot simply be hosed down, and are the stage most often forgotten. Left unserviced they blind over, raise the resistance the fan must overcome and quietly strangle the whole system's airflow.
The cleaning consequence is direct. Baffles reward a hot soak and a good degrease; mesh needs frequent washing and eventual replacement once the wires deform; cartridges need servicing or renewal on the maker's terms, not a rinse. Treating all three the same - or worse, ignoring the secondary stages - is how grease that a filter should have stopped ends up coating the plenum, the duct and the fan.
What it means for you
Identifying your filter type tells you what routine your kitchen needs. A canopy of baffles suits a daily wipe and a regular soak; a mesh-filtered hood needs washing far more often and honest budgeting for replacements; any secondary or cartridge stage needs a service interval of its own that staff cannot do at the sink. Match the routine to the filter and grease stays where it can be removed easily.
It also shapes what a professional clean should address. A good contractor checks not just the primary filters but the secondary stages and their housings, because those are where hidden resistance and grease build. If a quote only mentions the canopy filters, it may be leaving the very stages that most affect airflow and fire risk out of scope.
Getting the filter right upstream reduces everything downstream. A well-chosen, well-maintained filter drains or holds grease where you can deal with it cheaply, rather than passing it into the ductwork where removal is slow, disruptive and far more costly. The filter is the cheapest place in the whole system to control grease, which is exactly why its type and its care matter so much.
The service behind the guide
Sibling guides
How baffle filters work · Mesh filters and quick clogging · Frequency by cooking volume
Questions
For most commercial kitchens a stainless steel baffle filter is the primary choice. DW/172 specifies baffles because they capture grease efficiently, drain themselves, resist flame and clean easily. Mesh is used only as a secondary filter.
Because each traps grease differently. Baffles drain and soak clean, mesh holds grease and clogs so needs frequent washing, and cartridge or secondary stages hold grease deep and need servicing rather than a rinse.
Mesh holds grease in the wire, which can act as a path for flame and clogs quickly. Current guidance treats mesh as a secondary filter behind a baffle, not as a primary filter on its own.
The secondary and cartridge stages - honeycomb cells, coil filters ahead of UV, and fine media. They blind over, raise airflow resistance and are often left out of a routine clean.
No. Baffles reward a hot soak and degrease, mesh needs frequent washing and eventual replacement, and cartridge stages need servicing on the manufacturer's terms. The wrong method damages the filter or misses the grease.
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.