AAON (NASDAQ: AAON) designs, manufactures and sells semi-custom heating, ventilation and air conditioning equipment (HVAC) for commercial and residential use. Primarily, it "“makes and sells air conditioning and heating equipment for the new construction and replacement markets.”

AAON Inc. was founded by Norm Asbjornson in 1987, when he purchased the air conditioning and heating division of John Zink. Asbjornson became both founding president and CEO. As of June 2016, AAON employed 1,300 people at its headquarters in Tulsa, Oklahoma. It also employed approximately 300 people in Longview, Texas, with around $358 million in annual sales.

The company broke ground on a new R&D lab in Tulsa on February 25, 2016. At the time, AAON was also expanding its manufacturing facility nearby. The research lab will reportedly cost US $33 million, and will be ready in 2019.

Its subsidiary, AAON Coil Products manufactures a variety of heating/cooling products, as well as, coils used in the heating, ventilation, and air conditioning (HVAC) industry and provides coils to AAON as well as to other customers.