Constant air volume (CAV) is a type of heating, ventilating, and air-conditioning (HVAC) system.
[1] Most CAV systems are small, and serve a single thermal zone.
In mid- to large-size buildings, new central CAV systems are somewhat rare.
Due to fan energy savings potential, variable air volume (VAV) systems are more common.
Such small CAV systems often have on/off control, rather than supply air temperature modulation, to vary their heating or cooling capacities.