AAON, Inc., together with its subsidiaries, engages in engineering, manufacturing, marketing, and selling air conditioning and heating equipment in the United States and Canada. It offers rooftop units, chillers, packaged outdoor mechanical rooms, air handling units, makeup air units, energy recovery units, condensing units, geothermal and water-source heat pumps, self-contained units, coils, and controls. The company markets and sells its products to retail, manufacturing, educational, lodging, supermarket, medical, and other commercial industries. It sells its products through a network of manufacturers' representatives and internal sales force. The company was incorporated in 1987 and is based in Tulsa, Oklahoma.