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Kitchen air balance: what goes out has to come back in.
A commercial kitchen hood removes heat, smoke and grease-laden air — a lot of it. The make-up air system replaces it. When the two drift apart, the whole building feels it.
Starved, balanced, pushing.
On each seesaw, the grey block on the left is the air the hood pulls out; the green block on the right is the air brought back in. The beam tips toward the bigger one.
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Too little air in
Starved
The hood pulls out far more than comes back. The building goes negative and pulls air in wherever it can.
- Front and back doors hard to open, or slamming
- Cold drafts in the dining room in winter, hot and humid in summer
- Hood struggling to capture smoke, kitchen hot
- Gas appliance flues can be drawn backwards — a safety concern
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What you want
Balanced
Make-up air replaces nearly all of the exhaust. The kitchen sits a touch negative to the dining room, so cooking smells stay in the kitchen.
- Doors open normally
- Hood captures smoke cleanly
- Dining room comfortable, kitchen tolerable
- Rooftop units not fighting outside air
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Too much air in
Pushing
More air comes in than the hood removes. The building goes positive and pushes air out through every gap.
- Cooking smells pushed into the dining room
- Doors that won't stay shut
- Unconditioned make-up air overwhelming the kitchen's cooling
- Energy wasted heating or cooling air that leaves straight away
Diagrams are illustrative: they show direction, not measured airflow. We measure your hood and make-up air before recommending anything.
Balanced once doesn't mean balanced now.
- Menu or equipment changes
- A new fryer line or a longer hood changes the exhaust the kitchen needs.
- Worn belts and dirty filters
- Make-up air units lose airflow quietly until the building goes negative.
- Interlocks bypassed
- Make-up air that no longer starts with the hood — or never stops.
- Tenant changes
- A new restaurant in an old space, running the last tenant's equipment.
Measure, adjust, write it down.
Measure
Exhaust and make-up airflow checked, with the hood running as it does in service.
Adjust
Belts, filters, dampers and interlocks set so make-up air follows the hood.
Report
What we measured, what we changed and anything that needs replacing.
Hood and duct grease cleaning, fire suppression and health inspections are separate specialist trades — we coordinate with them, but don't do that work.
Restaurants and kitchens
Rooftop make-up air units, interlocks and dining-room comfort.
Big range hoods
Residential code generally requires make-up air for hoods above 400 cfm. We size and install it.
Ask for a balance check.
Booked before service or on your closed day.