Air handling unit

An air handler, or air handling unit (AHU), is a unit used to condition and circulate air as part of a heating, ventilating, and air-conditioning (HVAC) system, either fixed or temporary. Usually, an air handler is a large metal box containing a blower, heating and/or cooling elements, or coupled to a cooling or heating system. Air handlers usually connect to ductwork that distributes the conditioned air through the building, and returns it to the AHU. Sometimes AHUs discharge (supply) and admit (return) air directly to and from the space served, without ductwork equalising pressure. An AHU will also be used in conjunction with Chiller units to distribute air.