Even a simple VAV system has several advantages over a CAV system. One is more precise temperature control. To meet a space cooling load, a CAV unit operates the fan and compressor at full capacity until the temperature drops to a specified limit, and then the compressor turns off. This on/off cycling causes the temperature to fluctuate above and below the temperature setpoint. In a single-zone VAV unit, the fan speed varies depending on the actual space temperature and the temperature setpoint, while the compressor modulates the refrigerant flow to maintain a constant supply air temperature. The result is more precise space temperature control.