AAON was founded in 1988 with the acquisition of the heating and cooling division of another company. In the early 1990s, they became a major player — producing and supplying their own rooftop commercial units to large companies, such as Walmart. Nationwide Coils has the capability to replace coils for many AAON models, including RK, RM, RN, RL and RH. Just contact us with the existing unit or model number.