CAV, short for Constant Air Volume, is a HVAC damper which supplies air at constant airflows at a constant temperature ; unlike Variable Air Volume (VAV) devices, which supply a variable airflow at a variable temperature. Airflow is regulating by the rotating damper blade, depending on pressure changes into the ductwork, without any external power supply. The regulator makes system balancing unnecessary by ensuring a constant air volume.Constant air volume systems are very common in buildings like offices and hotels