What type of air is conveyed from a heat exchanger to an area used for human habitation?

The correct answer is supply air, as this type of air refers specifically to the conditioned air delivered from the heating or cooling system to a space where people live or work. In the context of HVAC systems, supply air is critical because it is the air that has been treated to reach a desired temperature and humidity level before being released into occupied areas.

The heat exchanger is responsible for transferring heat between two air streams—cooling or heating the air as necessary. The processed supply air enhances comfort and maintains the climate within the living or working environment.

Return air and exhaust air serve different functions within the HVAC system. Return air is the air that is pulled from the occupied space back into the system for reconditioning, while exhaust air is the air removed from the space to maintain air quality, usually venting it outside. Fresh air usually refers to unconditioned outside air that may be introduced into the system for ventilation, but it is not necessarily treated to be at a comfortable temperature or humidity before entering a living space.