Abstract: In one embodiment of the invention, conditioning means for providing air at a desired temperature are located adjacent to the front end of a vehicle. The conditioning means have an inlet adjacent the top of the vehicle and an outlet adjacent the bottom. Conditioned air flows from the outlet through an imperforate passageway along the bottom of the vehicle to the rear end of the vehicle where the conditioned air moves vertically through a passageway in the rear door and is discharged adjacent the top of the vehicle. The discharged conditioned air flows in normal convection paths back to the inlet of said conditioning means. In another embodiment, the conditioning means are located adjacent to the bottom of the vehicle between the front and rear ends thereof.