Kitchen ventilation is the most overlooked system in a commercial kitchen — until it fails. Here are five warning signs that your exhaust and makeup air system needs attention.
1. Smoke or Cooking Odors in the Dining Room
If customers can smell the fryer from their table, your exhaust system isn't capturing properly. This usually means:
- Exhaust fan speed has decreased (worn belt, failing motor)
- Makeup air unit isn't providing enough replacement air
- Kitchen is running at negative pressure, pulling air from the dining room instead of the other way around
The fix: Air balance test and fan service. A properly balanced kitchen should be slightly negative relative to the dining room — enough to contain cooking odors but not enough to pull conditioned air.
2. Excessive Heat in the Kitchen
Your kitchen is hotter than it should be. Staff is uncomfortable. Food quality suffers.
Common causes:
- Makeup air unit not functioning (kitchen is pulling hot unconditioned air from outside)
- Exhaust volume too low (heat isn't being removed)
- Makeup air temperature not being tempered in winter or cooled in summer
Why it matters: OSHA recommends kitchen temperatures below 86°F. Beyond comfort, excessive heat accelerates equipment wear, increases refrigeration costs, and affects food safety.
3. Grease Dripping from Hoods or Ductwork
Visible grease accumulation on hood surfaces, duct seams, or fan housings is a fire hazard. Commercial kitchen fires caused by grease buildup in ductwork account for thousands of incidents per year.
What to do:
- Schedule hood cleaning immediately (NFPA 96 requires quarterly for heavy-use kitchens)
- Have the ductwork inspected — grease may have accumulated in areas the cleaning crew can't reach
- Check that grease filters are being cleaned/replaced regularly by kitchen staff
4. Fan Making Unusual Noises
Grinding, squealing, rattling, or vibration from the exhaust fan means mechanical problems:
- Squealing: Belt slipping or worn
- Grinding: Bearing failure (replace immediately before total failure)
- Rattling: Loose mounting, debris in fan housing, or unbalanced fan wheel
- Vibration: Grease buildup on fan blades causing imbalance
A fan that fails completely shuts down your kitchen. These sounds are your warning — address them before they become emergencies.
5. Doors That Are Hard to Open or Slam Shut
If your front door requires extra force to open, or slams shut violently when released, your kitchen is running at excessive negative pressure. This means the exhaust is pulling out more air than the makeup air system is providing.
Consequences:
- Energy waste (pulling heated/cooled dining room air into the kitchen)
- Customer discomfort (drafts near the entrance)
- Equipment strain (refrigeration works harder against warm infiltration air)
- Backdrafting risk in gas appliances
The fix: Professional air balance measurement and makeup air system service.
How Air Balancing Works
A qualified technician uses instruments to measure:
- Exhaust airflow at each hood section (CFM)
- Makeup air supply volume
- Pressure differential between kitchen and dining room
- Temperature of supply air
The goal: kitchen at -0.02 to -0.05 inches of water column relative to the dining room. Enough to contain odors, not enough to cause problems.
Ventilation Maintenance Schedule
| Service | Frequency |
|---|---|
| Grease filter cleaning | Weekly (kitchen staff) |
| Hood cleaning | Quarterly |
| Fan belt inspection | Quarterly |
| Full air balance test | Semi-annually |
| Ductwork inspection | Annually |
| Fire suppression inspection | Semi-annually |
True Commercial Service specializes in commercial kitchen ventilation systems including CaptiveAire hoods, makeup air units, and exhaust fan service. We perform air balancing, fan repair, and ongoing maintenance across Union County, NJ.
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Looking for service? Visit our Kitchen Ventilation Service page or schedule service today.