AAON Inc is a manufacturer of air-conditioning and heating equipment. The products include rooftop units, chillers, packaged outdoor mechanical rooms, air-handling units, makeup air units, energy-recovery units, condensing units, geothermal heat pumps, and self-contained units and coils. The company operates through three segments: AAON Oklahoma, AAON Coil Products, and BASX. It generates the majority of its revenue from the AAON Oklahoma segment which engineers, manufactures, and sells, semi-custom, and custom HVAC systems, designs and manufactures control solutions, and sells retail parts to customers through retail part stores and online.