Fan coil units (FCUs) are versatile heating and cooling devices commonly used in residential and commercial HVAC systems. They consist of a fan and a coil, which circulates water or refrigerant to transfer heat to or from the air. FCUs can be installed in various configurations, including ceiling-mounted, wall-mounted, or floor-mounted, making them suitable for a wide range of spaces. They offer efficient temperature control and are often used in conjunction with centralized systems, providing localized comfort while maintaining energy efficiency. Their compact design and quiet operation make them an ideal choice for both new constructions and retrofits.