Heat, energy & performance
The single biggest lever on kitchen temperature is the extract system working at its design airflow. Fans, blinds and cold drinks help at the margins, but if the canopy is not clearing the heat plume, the room bakes. A clean, balanced extract does more than any portable cooler.
The short answer
The single biggest lever on kitchen temperature is the extract system working at its design airflow. Fans, blinds and cold drinks help at the margins, but if the canopy is not clearing the heat plume, the room bakes. A clean, balanced extract does more than any portable cooler.
The detail
A commercial kitchen makes its own weather. Ovens, ranges, fryers and salamanders throw off a rising column of hot, moist, grease-laden air - the plume. The canopy exists to catch that plume at source and carry it out through the filters, plenum, duct and fan before it spills into the room. When it works, most of the heat leaves before anyone feels it.
That capture depends on airflow. DW/172, the BESA specification for kitchen ventilation, sizes the extract rate around the cooking load so the canopy holds a capture velocity across its face. Lose that airflow and the plume rolls out of the canopy edges into the working area, and the room temperature climbs regardless of what the wall thermostat says.
Air conditioning and portable fans move existing room air around; they do not remove the heat the appliances are still pouring in. Extraction is the route that actually takes heat out of the building. If the extract is under-performing, cooling equipment simply fights a losing battle against a source it was never sized to beat.
Grease is what quietly steals the airflow. It loads the filters and coats the duct, raising resistance so the fan moves less air than designed. A system that captured cleanly in spring can be spilling heat by July, and the cause is not the weather - it is a canopy overdue a clean.
What it means for you
The law frames this as a duty. The Workplace (Health, Safety and Welfare) Regulations 1992 require a reasonable indoor temperature, and the approved code sets a normal minimum of 16C, or 13C where the work is strenuous. There is no legal maximum, so heat is treated as a hazard to assess and control - and extraction is the front-line control.
Practically, the order of priority is airflow first. A clean, balanced extract with make-up air at around 85% of the extract rate clears heat and steam and keeps the room from going negative. Only then do fans, blinds and hydration make a real dent, because they are working with a system that is already removing the heat load.
The cheapest cooling upgrade most kitchens can make is a clean. Phoenix Duct Clean restores the extract to its TR19 Grease condition so the canopy pulls its design airflow again - the difference between a workable service and a sweltering one.
The service behind the guide
Sibling guides
Why grease makes a kitchen hotter · The energy cost of a clogged fan · Takeaway extraction cleaning
Questions
Rarely. Air conditioning recirculates room air but does not remove the heat the appliances keep producing. Extraction is the route that carries heat out of the building, so a clean, well-sized extract has to come first for cooling to work.
Grease gradually loads the filters and duct, raising resistance so the fan moves less air than it did when commissioned. Capture velocity drops and the heat plume starts spilling into the room. A clean restores the original airflow.
There is no legal maximum, but the Workplace Regulations require a reasonable temperature. The approved code sets a normal minimum of 16C, or 13C for strenuous work. Kitchen work is strenuous, so comfort sits at the lower end of the range.
Yes. If extracted air is not replaced, the room goes negative and pulls in warm uncontrolled air through doors and gaps. Balanced make-up air at around 85% of the extract rate keeps the system working as designed.
Immediately. Once filters, plenum and duct are back to TR19 condition the fan meets its design airflow again on the same day, so capture velocity and heat removal recover as soon as the system is switched back on.
Phoenix Duct Clean · by the numbers
Book a TR19 extraction clean and get the airflow back before the next heatwave.