Size your kitchen exhaust system correctly. Enter your hood dimensions and equipment details to calculate the required exhaust CFM, make-up air, and estimated costs per IMC standards.
Required Exhaust Airflow
4,000 CFM
Based on Wall Canopy hood, Heavy duty, 10 ft length (400 CFM/ft)
Exhaust CFM
4,000
Make-Up Air CFM
3,200
80% of exhaust
Annual Energy Cost
$2,707
$226/mo
Fan Power Required
6 HP
4.5 kW
Estimated Equipment Cost
$60,000 - $100,000
Hood, ductwork, fans, make-up air unit
Hood Area
40 sq ft
10 ft x 4 ft
| Hood Type | Light | Medium | Heavy | Extra-Heavy |
|---|---|---|---|---|
| Wall Canopy | 200 | 300 | 400 | 550 |
| Island | 300 | 400 | 500 | 700 |
| Proximity / Backshelf | 150 | 250 | 300 | 400 |
Values in CFM per linear foot of hood. Your selection is highlighted.
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This tool uses the International Mechanical Code (IMC) exhaust rate tables to determine the required CFM for your commercial kitchen exhaust hood. The calculation is based on hood type, equipment duty level, and hood length.
The IMC prescribes minimum exhaust rates in CFM per linear foot of hood length. The rate depends on the hood configuration (wall canopy, island, or proximity/backshelf) and the highest duty rating of the equipment beneath the hood. Make-up air is typically designed at 80% of the exhaust volume to maintain a slight negative pressure in the kitchen.
| Kitchen Type | Typical CFM Range | Estimated Cost |
|---|---|---|
| Small restaurant (8 ft hood) | 1,600 - 3,200 CFM | $24,000 - $80,000 |
| Medium restaurant (12 ft hood) | 2,400 - 4,800 CFM | $36,000 - $120,000 |
| Large commercial kitchen (16+ ft) | 3,200 - 8,800 CFM | $48,000 - $220,000 |
| Charbroiler-heavy operation | 4,400 - 8,800+ CFM | $66,000 - $220,000+ |
Local codes may require higher rates than IMC minimums. Always verify with your local authority having jurisdiction (AHJ). Additional factors include hood overhang, ceiling height, proximity to HVAC diffusers, and fire suppression system requirements.