An air conditioning system and methods of use regulate a moisture content of an agricultural product in a grain bin. The system receives headspace air from the headspace of the grain bin, which generally has a higher moisture content than ambient air. The system further receives ambient air and mixes the headspace air and the ambient air into a ratio comprising a target moisture content. The air mixture is provided into a grain bin plenum, where it then permeates through to agricultural product, thereby regulating the moisture. The system and method can be used to bring the agricultural product to a target moisture content that is preferred when storing the agricultural product.