AAON, Inc. engages in the engineering, manufacturing, marketing and sale of air conditioning and heating equipment. It consists of standard, semi-custom and custom rooftop units, chillers, packaged outdoor mechanical rooms, air handling units, makeup air units, energy recovery units, condensing units, and geothermal/water-source heat pumps and coils. Read More It operates through the following segments: Units, Parts, and Other. The Sales segments represents the selling price of its units plus freight, and other miscellaneous charges less any returns and allowances. The Parts segment represents the sales of purchased, and fabricated parts including coils along with the related freight. The Other segment covers certain sales cost and expenses that are not allocated to the reportable segments. The company was founded by Norman H. Asbjornson on August 18, 1987 and is headquartered in Tulsa, OK.