frequency · 5 min read · Updated 2026-02-18
Signs Your Kitchen Exhaust System Needs Cleaning
Ten specific signs that a commercial kitchen exhaust system is overdue for cleaning, with notes on severity and what to do next.
Visible signs
- Grease visibly dripping from filters or pooling on the cook line.
- A dark grease halo forming on the ceiling above the hood.
- Thick, crusted grease on the exterior of the hood.
- Visible grease staining on rooftop membrane near the fan.
Smell and air quality
- A persistent rancid smell that doesn't go away with surface cleaning.
- Smoke that lingers over the grill instead of pulling up into the hood.
Performance signs
- Reduced airflow when the exhaust fan is on.
- Fan motor working harder than it used to (higher amp draw).
Compliance signs
- Your last inspection report cited cleaning frequency or documentation.
- You can't remember or find your last cleaning certificate.
Frequently asked questions
- Can I just clean the visible grease myself?
- Wipe-downs are useful between professional cleanings, but they do not substitute for duct and fan cleaning, which require specialized equipment.