Canopy, filters & fan
Two kitchens can run the same hours and need completely different cleaning routines, because what they cook decides how fast grease loads the system. A wok range, a chargrill and a deep fryer throw far more airborne grease than steaming or baking - so cooking style, not just opening hours, should set your filter and cleaning frequency.
The short answer
Two kitchens can run the same hours and need completely different cleaning routines, because what they cook decides how fast grease loads the system. A wok range, a chargrill and a deep fryer throw far more airborne grease than steaming or baking - so cooking style, not just opening hours, should set your filter and cleaning frequency.
The detail
Airborne grease comes from cooking that atomises fat into the extract stream, and some methods do this far more than others. High-heat wok cooking throws oil into the air with every toss; chargrilling drips fat onto flame that vaporises it straight up into the canopy; deep frying sends a fine oil mist off the surface of the oil. These are the heavy-loading styles that grease a system fast.
At the other end, cooking that keeps fat contained loads the system slowly. Steaming, boiling and much baking produce mostly moisture and little airborne grease, so a kitchen built around them can run far longer between filter soaks and system cleans than a grill house on the same hours. Combi ovens and induction with covered pans sit lower on the scale than open flame and open oil.
This is why TR19 Grease frames its intervals around usage and risk rather than hours alone, and why a specialist sets frequency from inspection, not a formula. A heavy-grease kitchen may need filters soaked daily and the system cleaned every three months, while a light-use, low-grease kitchen on similar hours may sit comfortably at six-monthly or beyond. The menu is the variable that the clock hides.
Mixed kitchens follow their worst offender. A menu that is mostly light but includes a busy chargrill or fryer loads the system at the rate of that heavy station, not the average, because all the extract shares the same canopy and duct. The frequency has to suit the greasiest cooking in the kitchen, not the gentlest, or the heavy station quietly outpaces the schedule.
What it means for you
The practical rule is to set frequency by what you actually cook, confirmed by inspection. A kitchen leaning on wok, grill or fryer should assume the heavy end of the interval range and watch its filters closely; a lighter kitchen can justify a longer interval, but only once measurement confirms the grease build-up is genuinely slow. Copying another kitchen's schedule without matching the cooking is how systems fall behind.
It also guides where to put attention. In a heavy-grease kitchen the filters are the front line and need daily discipline, because everything the menu throws off hits them first; letting them load simply speeds grease into the duct. The greasier the cooking, the more the cheap daily filter routine pays off in slower system loading downstream.
Setting the interval honestly protects both safety and cost. Under-cleaning a heavy-grease kitchen lets the duct load past safe limits between visits; over-cleaning a genuinely light one wastes money. Matching the frequency to the cooking style, and adjusting it as the menu changes, is what keeps the system both compliant and economical rather than guessed at.
The service behind the guide
Sibling guides
Replacing filters vs cleaning them · What extraction cleaning covers · Frequency by cooking volume
Questions
Yes, significantly. Wok cooking, chargrilling and deep frying throw far more airborne grease than steaming or baking, so two kitchens on the same hours can need very different filter and cleaning routines.
High-heat wok cooking, chargrilling over flame and deep frying all atomise fat into the extract stream. These load filters and ductwork far faster than steaming, boiling or most baking.
TR19 Grease frames intervals around usage and risk, not hours alone. A heavy-grease kitchen may need three-monthly system cleaning while a light one on similar hours can sit at six-monthly or beyond.
A mixed kitchen loads at the rate of its greasiest station, because all the extract shares one canopy and duct. The frequency must suit the heaviest cooking, not the average.
By what you actually cook, confirmed by inspection and measurement. Assume the heavy end of the range if you rely on wok, grill or fryer, and only stretch the interval once readings show slow build-up.
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.