This topic covers information related to HVAC fans installed as part of HVAC systems during construction. HVAC fans can be one of several types; axial, centrifugal, power ventilators or air curtains. Axial fans in construction are commonly known as ceiling fans. Centrifugal fans are commonly found in mechanical units that distribute air. Power ventilators are used to draw air from a room or portion of a structure and remove heat and/or moisture, such as attic vents and gable vents. Air curtains are stand alone devices that generate a wall of air that separates two spaces, such as an entry from the outdoors to the indoors.