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Bathroom Fan Ratings - Code Compliance Brief

If the bathroom fan is part of the whole-house mechanical ventilation system (WHMV), there are code provisions that should be verified during plan review and field inspection depending upon codes enforced in your jurisdiction.

Plan Review
  • Review fan specifications meet cfm and cfm/W (efficacy/energy efficiency)

2012 IECC, Table 403.5.1

Fan Location Airflow Rate Minimum (cfm) Minimum Efficacy (cfm/W) Airflow Rate Maximum (cfm)
Bathroom, utility room 10 1.4 < 90
Bathroom, utility room 90 2.8 Any
  • Verify all fans that are part of the WHMV meet efficacy requirements
Field Inspection
  • Confirm fan(s) meet the approved efficacy (matches what was plan reviewed)

Note:  the cfm/W might not be shown on the fan (label), refer to technical specifications.

Technical Validation(s)

Building Energy Codes Program -

Code Note - Residential Fan Efficiency