A Fan Coil Unit (FCU) is a type of HVAC (Heating, Ventilation, and Air Conditioning) system that is used to control the temperature and air quality in a space. It is typically installed in commercial and industrial buildings, but can also be used in residential settings. The FCU is a self-contained unit that consists of a fan, a coil, and a control system. The fan is used to move air through the system, while the coil is used to heat or cool the air. The control system is used to regulate the temperature and air quality in the space. The FCU is a cost-effective way to control the temperature and air quality in a space, as it is relatively easy to install and maintain. Additionally, the FCU can be used to reduce energy costs by controlling the temperature and air quality in the space more efficiently.