What is wrong? › Commercial HVAC
A hood that is not pulling is a fire risk, and it is a hood contractor's job
NFPA counts an average of 7,410 structure fires a year in eating and drinking establishments, and three out of five involve cooking equipment. Grease that is not being pulled out is fuel sitting over your line.
What is probably happening
- The exhaust fan on the roof has stopped: a broken belt, a failed motor, or its own breaker tripped.
- Grease-loaded filters or a grease-clogged duct. NFPA 96 requires the whole exhaust system to be inspected for grease by a trained and certified person, monthly for solid fuel, quarterly for high volume, semiannually for moderate, annually for low volume cooking.
- No makeup air: the rooftop unit or makeup air fan is off, the kitchen goes into negative pressure, and the hood cannot pull.
- This is a different trade from your HVAC unit. Kitchen exhaust cleaning and hood ventilation contractors do this; your fire suppression company may also need to check the system.
Do this in the next five minutes
- Stop cooking under that hood until it pulls. Open a back door for now to relieve negative pressure.
- Check the hood fan switch and the fan's breaker. Reset once. If it trips again, leave it.
- Pull the grease filters. If they are heavy with grease, run them through the dishwasher now. If the duct behind them is coated, do not restart cooking.
- Find your last hood cleaning certificate. The sticker on the hood shows the date. If it is past the NFPA 96 interval for your cooking volume, book a cleaning.
- Call a kitchen exhaust hood contractor. If the fan itself has failed, a commercial HVAC contractor can also replace a roof exhaust fan.
Do not
- Do not cook with the hood off. A grease fire with no exhaust fills the room in seconds.
- Do not spray anything into a grease-coated duct.
- Do not let a general HVAC tech 'clean the hood'. NFPA 96 wants a trained, qualified and certified person acceptable to your fire authority.
Who to call
A kitchen exhaust hood cleaning and ventilation contractor, not a comfort cooling technician
Hood cleaning, duct inspection and makeup air balance are a specialty with their own certifications and fire code. A commercial HVAC contractor handles the roof fan motor and belt if that is all it is.
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What it should cost
$100 to $250 per hour
HVAC labor for a roof exhaust fan belt or motor. No neutral national figure for hood cleaning was found, so ask for a fixed price per cleaning
Source: Angi, HVAC repair cost, updated August 2026. View source
National published range, not a quote for your job. The full cost table for this trade is on the commercial hvac page.
Ask this contractor, on the phone, before anyone comes out
Tap each one as you ask it.
- Are you certified for kitchen exhaust cleaning to NFPA 96, and will you leave a dated certificate and sticker?
- Will you inspect the whole duct run to the roof fan, not just the hood, and photograph it?
- Is my makeup air working, and is the kitchen under negative pressure?
- What cleaning interval do you recommend for my cooking volume, and why?
- Does the roof fan need a hinge kit or a grease containment tray to be compliant?
End the call if
- A cleaning that only touches the hood canopy and filters.
- No certificate, no sticker, no photos of the duct after cleaning.