a plurality of ducts lead to corresponding outlet nozzles not shown for supplying conditioned air to separate regions in the occupant compartment of the motor vehicle a ventilation duct 5 a defroster duct 6 and a foot duct 7 conduct conditioned air to a front section of one side of the vehicle the ducts 5 6 and 7 are associated with an upper segment 8 of the heater 4 however the ventilation duct 5 is adjacent a side wall of a housing 110 and the air stream conducted by the ventilation duct 5 does not pass through the heater 4 associated with a lower segment 9 of the heater 4 are a foot duct 10 and a ventilation duct 11 for conducting conditioned air to a rear section of the same side of the vehicle as with the front zone ventilation duct 5 the ventilation duct 11 is adjacent a side wall of a housing 110 and the air stream conducted by the ventilation duct 11 also does not pass through the heater 4 generally the defroster duct 6 is for conducting conditioned air to an upper region of the front section and the ventilation ducts 5 11 are for conducting conditioned air to regions within their respective sections which are relatively higher in the passenger compartment than the regions receiving conditioned air conducted by the foot ducts 7 10 the illustrated arrangement of the ducts 5 7 10 and 11 makes independent temperature setting simple arranging the ventilation ducts 5 11 adjacent the side walls of the housing 110 permits cooled air leaving the refrigerant condenser 3 to circumvent the heater 4 through respective bypasses 12 13 one or more air valves or mixing flaps.