Heat, energy & performance
Air conditioning and extraction are meant to share the work: extract removes the cooking heat at source, and cooling handles the rest. When a greased extract stops pulling its weight, the heat and humidity it should have removed land on the cooling plant instead, and the air-conditioning bill climbs to cover the gap.
The short answer
Air conditioning and extraction are meant to share the work: extract removes the cooking heat at source, and cooling handles the rest. When a greased extract stops pulling its weight, the heat and humidity it should have removed land on the cooling plant instead, and the air-conditioning bill climbs to cover the gap.
The detail
The design intent is a division of labour. The canopy captures the concentrated heat plume straight off the appliances and takes it out of the building. Comfort cooling then handles the residual room heat gain from people, lights and the fabric. Each system is sized for its share.
When grease cuts the extract airflow, that division breaks down. Heat and steam that should have left through the duct spill into the room instead, and the cooling plant now has to remove a load it was never sized for. It runs longer and harder to hold the same room temperature.
Humidity makes it worse. Uncleared steam adds latent heat - moisture the cooling coil has to condense out before it can lower the temperature. Latent load is expensive to remove, so a steamy kitchen from a weak extract is a particularly costly thing to ask air conditioning to fix.
Negative pressure adds a third cost. If the extract is unbalanced and the room goes negative, it pulls untreated outside air in through doors and gaps. That air arrives at whatever temperature and humidity the day offers, undoing the cooling and loading the plant even further.
What it means for you
If the air conditioning seems to run constantly and still cannot hold the kitchen, the extract is a prime suspect. Cooling plant asked to cover a failed extract is working against a source it cannot beat, which shows up as long run times and rising cost rather than a comfortable room.
Fixing the extract lightens the cooling load. With airflow and capture restored by a TR19 clean, the canopy takes the cooking heat and humidity out at source again, and the cooling plant returns to the residual load it was actually sized for.
Phoenix Duct Clean restores the whole extract path, so the two systems share the work as intended - and the air conditioning stops paying for grease in the duct.
The service behind the guide
Sibling guides
Staff comfort and productivity · Cutting kitchen humidity · Cafe extraction cleaning
Questions
Yes. Extraction is meant to remove cooking heat at source. When grease cuts its airflow, that heat and humidity spill into the room and the cooling plant must remove a load it was never sized for, running longer and costing more.
Steam adds latent heat - moisture the cooling coil must condense out before it can lower the temperature. Latent load is costly to remove, so uncleared steam from a weak extract is an expensive thing for air conditioning to handle.
An unbalanced extract can pull the room negative, drawing untreated outside air in through doors and gaps. That air arrives hot or humid and undoes the cooling, loading the plant further. Balanced make-up air prevents it.
Long, near-constant cooling run times that still cannot hold the kitchen are a warning sign. If the extract has also lost airflow to grease, it is likely dumping heat the cooling plant is then fighting.
It should ease them. Restoring extract airflow means the canopy removes cooking heat and humidity at source again, so the cooling plant returns to the residual room load it was actually sized to handle.
Phoenix Duct Clean · by the numbers
A weak extract often loads the cooling plant. Book a TR19 clean to share the work again.