A air handler unit (AHU) is a device used to condition and circulate air as part of a heating, ventilating, and air-conditioning (HVAC) system. An AHU consists of a blower, heating and/or cooling elements, filter racks or chambers, sound attenuators, and dampers. The blower is used to draw air into the unit and circulate it through the building. The heating and/or cooling elements are used to add or remove heat from the air, depending on the season. The filter racks or chambers are used to remove dust and other airborne particles from the air. The sound attenuators are used to reduce the noise generated by the blower. Finally, the dampers are used to control the flow of air through the unit. AHUs are an important part of any HVAC system, as they are responsible for providing a comfortable environment for the occupants of a building.