Compact air treatment device for a motor vehicle

The device has a selection unit (8) to select exterior or re-circulated air. A water separation unit, the unit (8), a filter (9), and a fan (20) for cooling, heating, and air-conditioning a vehicle are placed in a common case (1) fixed over a partition (5) separating a driving compartment from a passenger cabin (4). The partition has openings for passage of the re-circulated air, and the filtered air to the fan.