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 <90 2.8 Other exhaust fan ≥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.