Box fans are a centrifugal impeller and motor housed in a box structure which usually has added sound attenuation and sometimes have configurable panels allowing for the inlet and outlet to either be run in-line or at a 90° angle. Box fans use centrifugal impellers which can generate higher pressures than axial fans. Box fans are most often used in building ventilation and commercial kitchen extract systems.
Box fans are sometimes suitable for external installations on roofs as well as being used internally, often housed in the ceiling void.
Box fans are typically used in commercial buildings such as offices, public buildings, factories, retail stores and schools.