Fan Coil Unit (FCU), also known as a Vertical Fan Coil-Unit (VFC), is a device consisting of a heat exchanger (coil) and a fan. As part of an HVAC system found in residential, commercial, and industrial buildings using ducted split air conditioning or with central plant cooling, a fan coil unit is often connected to ductwork and a thermostat to regulate the temperature of one or more spaces as well as assisting the main air handling unit for each space if used with chillers. The thermostat controls the fan speed and/or the throughput of water to the heat exchanger using a control valve.