Abstract: An air transfer system for conveying air from the heater-air conditioner of a vehicle to the interior of an accessory such as a camper, trailer, and the like attached to the vehicle. The air transfer system includes a main conduit that is attached at one end to the air spreader of the heater-air conditioner of the vehicle to receive conditioned air therefrom. In one embodiment, the main conduit is positioned under or over the front seat of the vehicle and the other end of it passed through a hole in the back window of the vehicle and mounted to an adaptor positioned adjacent a hole in the front window of the camper. In two of the embodiments, the ends of the main conduit have collars that are slideably receivable within adaptors mounted to the air spreader and the window of either the vehicle of the camper. A third embodiment has a collar mounted around the main conduit adjacent its second end.