Section 460.204 - Mechanical ventilation fan efficacy(a) Whole-house mechanical ventilation system fans must meet the minimum efficacy requirements set forth in table 1 to 460.204(a), except as provided in paragraph (b) of this section. The mechanical ventilation fan efficacy requirements are adapted from section R403 of the 2021 IECC. Table 1 to § 460.204(a) -Mechanical Ventilation System Fan Efficacy
| Fan type description | Airflow rate
minimum
(cfm) | Minimum
efficacy
(cfm/watt) |
| Heat recovery ventilator or energy recovery ventilator | Any | 1.2 |
| In-line supply or exhaust fans | Any | 3.8 |
| Other exhaust fan | [LESS THAN]90 | 2.8 |
| Other exhaust fan | [GREATER THAN EQUAL TO]90 | 3.5 |
(b) Mechanical ventilation fans that are integral to heating, ventilating, and air conditioning equipment, including furnace fans as defined in § 430.2 of this subchapter, are not subject to the efficiency requirements in paragraph (a) of this section.