Abstract: The invention concerns a heating/air conditioning installation for the passenger compartment of a vehicle.It comprises treatment means produced in the form of at least one removable box suitable for being installed underneath the floor of the vehicle and containing an air inlet, an optional evaporator, a heating radiator and at least one air outlet suitable for being connected to distribution vents distributed within the passenger compartment.

Abstract: A motor vehicle heating and ventilating, and/or air conditioning, installation includes a heating and air distribution unit comprising a casing, the inlet of which is connected to the delivery side of a motorised fan unit. The casing has two outlets, namely a "feet" outlet leading to a lower part of the cabin of the vehicle, and a ventilation outlet, also leading into the cabin. The casing is divided into three ducts. Each of the first and second ducts has an upstream end open at the inlet of the casing, and a downstream end communicating with the feet and ventilation outlets of the casing respectively, under the control of a first flap valve and a second flap valve respectively. The third duct lies between the first and second ducts and has a central portion containing a heat exchanger.