Vav Fan Powered Boxes are an air distribution system designed to provide air conditioning and heating in commercial buildings. They consist of two fan units connected to supply-and-return ducts, each powered by its own electric motor. The two fans are typically connected in series, so that when one fan is running at low speed, the other fan runs at high speed, providing enhanced ventilation and increased energy efficiency. Vav Fan Powered Boxes are typically used in large-scale air systems, where energy savings are a priority.