Clean air fans supply fresh air for the general ventilation of a structure. These fans use a propeller that's directly mounted on the motor shaft. This reduces friction and improves efficiency compared to a belt-drive fan. Direct-drive fans have fewer moving parts and typically require less maintenance than belt-drive fans.

Clean air belt-drive fans with hinged hoods supply fresh air for the general ventilation of a structure. These fans come with a drive package that includes a motor, sheaves, belts, and bushings. They feature hinged hoods that swing open and expose the ventilator fan components for cleaning, maintenance, or service. Belt-drive fans are typically quieter and provide more control over the fans' blade speed and airflow than direct-drive fans.