A commercial kitchen relies heavily on a well-designed ventilation system. When it works correctly, it keeps the workspace comfortable, removes smoke and grease, protects equipment, and maintains safety. When it doesn’t, problems appear fast — and they can affect everything from food quality to employee health. Below are the most common issues found in commercial kitchen ventilation systems and what causes them.

1. Poor Airflow and Negative Pressure

One of the most frequent problems is unbalanced airflow. If exhaust hoods remove more air than the make-up air system supplies, the kitchen develops negative pressure. This leads to:

  • Doors slamming or staying hard to open

  • Smoke drifting into dining areas

  • Reduced hood capture efficiency

The root cause is usually incorrect hood sizing, a blocked duct, or inadequate make-up air supply.

2. Excessive Heat in the Kitchen

If employees complain about a hot kitchen, the ventilation system may not be removing heat correctly. Common causes include:

  • Undersized hoods

  • Dirty filters or grease buildup

  • Exhaust fans running at low performance due to wear

Overheating reduces productivity and can lead to equipment damage.

3. Smoke and Grease Not Fully Captured

When smoke escapes the hood, the problem often comes from:

  • Improper hood placement

  • Short overhangs

  • Low exhaust CFM

  • Incorrect hood type for the appliances

Grease that bypasses filters can also accumulate in ducts, increasing fire risk.

4. Loud or Vibrating Fans

Excessive noise usually means something is wrong in the fan system:

  • Loose belts

  • Worn bearings

  • Bent blades

  • Fans running outside their recommended RPM

Ignoring these issues can shorten equipment lifespan and lead to sudden failures.

5. High Energy Costs

A poorly optimized ventilation system wastes energy. Common reasons include:

  • Fans running at full speed all day

  • No demand-control ventilation

  • Leaky ducts

  • Oversized fans or unnecessary air changes

Simple adjustments can significantly reduce operating costs.

6. Frequent Hood or Duct Cleaning Issues

If grease builds up too fast, it may be due to:

  • Inefficient filters

  • Incorrect filter angle

  • Fans not exhausting enough air

  • Cooking appliances positioned too far from the hood

Grease buildup is a major fire hazard, so resolving these issues quickly is essential.

7. Make-Up Air Problems

Make-up air (MUA) replaces the air removed by the hood. When MUA is not working correctly:

  • Kitchen comfort drops

  • Airflow balance is lost

  • Exhaust performance decreases

Common causes include blocked MUA units, broken heaters, or misconfigured dampers.

Final Thoughts

A healthy commercial kitchen ventilation system is not “set it and forget it.” Regular inspections, proper sizing, and preventive maintenance avoid most problems before they start. When airflow, fan performance, and hood configuration work together, the kitchen stays safer, cooler, and more efficient.