A plenum box is an enclosed chamber in an HVAC system that serves as a central hub for air distribution. It connects ductwork to the main air handling unit (AHU) or fan coil unit (FCU). A fan powered box (FPB) is a specialized terminal unit used extensively in commercial and large multi-zone heating, ventilation, and air conditioning (HVAC) systems. It is compatible with Aerfoam insulated ducts and features 24 Air Excellent AE34C duct connections. With DBOX adaptors, it can connect to any. The Air Conditioning Distribution Box is a critical electrical component that centralizes power distribution for cooling systems while providing protection and ease of maintenance.