A Fan Coil Unit (FCU) provides heating and/or cooling via a heat exchanger (the coil) and fan (see example image below). Hot and/or cold water is circulated through a coil within the FCU with a fan passing air across the coil and into the space that is to be temperature controlled.

These units can be found in a number of diverse applications including offices, residential apartments, hospitals, hotels and schools. The FCU heat output is controlled using a control valve linked to the room via a thermostat. This in turn would be connected to a Building Management System (BMS), which controls the throughput of water to the heat exchanger.