A fan coil unit (FCU), also known as a Vertical Fan Coil-Unit (VFC), is a simple device consisting of a heating and/or cooling heat exchanger or 'coil' and fan. It is part of an HVAC system found in residential, commercial, and industrial buildings. A fan coil unit is a diverse device sometimes using ductwork, and is used to control the temperature in the space where it is installed, or serve multiple spaces. It is controlled either by a manual on/off switch or by a thermostat, which controls the throughput of water to the heat exchanger using a control valve and/or the fan speed.
A fan coil unit (FCU) contains a fan which draws the air in a space into the unit then blows it over a cooling or heating coil. The air comes out of the FCU either cooler or hotter than before. They are used in some office buildings and shopping centres and typically specified where there are multiple small spaces requiring individual control. Typically an individual FCU serves only up to 150m², so there can be tens or even hundreds in a building. FCUs are, however, most commonly used as a supplement to a building for which other HVAC systems provide the majority of the air-conditioning.
FCUs will generally have a chilled water coil for cooling and either a hot water coil for heating or an electric heating element. Chilled water is provided from a chiller located in the central plant, and hot water form a boiler.