A heating/air-conditioning device suitable for housing in a vehicle flat instrument panel

The device has a case (10) placed in front of a passenger compartment, and a partition (22) in the case to define two pipes. A cold air production unit (28) produces and sends a flow of cold air into one pipe. A heating radiator (40) placed at an interface of the pipes is traversed by the air and produces a flow of warm air in the other pipe. Distribution flaps are linked to air outlets (42) at the interface.