10 C.F.R. § 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 rateminimum(cfm)	Minimumefficacy(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.