A fan coil is a type of heating and cooling device commonly used in buildings to regulate indoor temperature. It consists of a fan and a coil filled with either hot or cold water, allowing it to transfer heat to or from the air. Fan coils can be installed in various locations, such as ceilings, walls, or floors, and are often part of a larger HVAC system. These units operate by drawing air from the room, passing it over the coil, and then circulating the conditioned air back into the space. Fan coils are efficient and versatile, making them suitable for both residential and commercial applications.