Choosing the correct hood size isn’t just a design choice—it’s essential for safety, performance, and ventilation compliance. Undersized hoods cause smoke overflow, grease buildup, and poor air quality. Oversized hoods waste energy and increase project costs. Here’s a simple guide to getting the sizing right.

1. Know Your Equipment Lineup

Start by listing all appliances under the hood: fryers, ranges, griddles, charbroilers, ovens, or specialty high-heat units. Each one affects required airflow (CFM) and hood dimensions.

2. Measure the Cooking Surface

The hood must extend beyond the equipment:

  • At least 6 inches on the front.

  • At least 6 inches on each side.

Example: If your cooking line is 72" wide, the hood should be around 84" wide.

3. Determine the Hood Depth

Front-to-back sizing is usually based on hood type:

  • Wall-mounted canopy hoods: typically 48" deep.

  • Island hoods: often 54" deep.

This ensures the capture area can pull smoke and heat upward effectively.

4. Calculate the Required CFM

Different appliance types require different exhaust rates. General guidelines:

  • Light-duty equipment: ~150 CFM per linear foot

  • Medium-duty: ~300 CFM per linear foot

  • Heavy-duty / charbroilers: 400–600+ CFM per linear foot

Multiply by the hood width to estimate total airflow.

5. Check for Makeup Air Requirements

Every CFM exhausted must be replaced. Poor makeup air causes:

  • Drafts

  • Low capture

  • Comfort issues for staff

Balancing supply and exhaust is key for code compliance.

6. Follow Local Codes and Standards

NFPA-96, IMC, and local jurisdictions may have additional rules for:

  • Minimum overhangs

  • CFM requirements

  • Grease filter angles

  • Fire suppression clearance

Always confirm before finalizing the hood size.

7. When in Doubt—Go Slightly Larger

A hood that’s a bit wider captures heat and smoke more reliably, especially with high-heat appliances or long cook lines.

Final Thoughts
Getting the right hood size is a combination of appliance layout, ventilation needs, and safety codes. With accurate measurements and proper airflow calculations, you’ll ensure a cleaner, safer, and more efficient kitchen.