The airflow that returns to the HVA system either by free air transfer or ducting through the floor or ceiling.

air re-circulated through a return air system to an air handling unit or furnace

Air drawn into a heating unit after having been circulated from the heater's output supply to a room.

Air pulled from a space and returned to the central air-conditioning plant for reconditioning.

Air removed from an approved conditioned space or location and recirculated or exhausted.

Air that is returned to a heating or cooling appliance from a heated or cooled space.

Air heated by the container cargo delivered to the evaporator. The temperature of return air often controls the operation of the refrigeration unit.