Vehicle air conditioning apparatus with two mixing zones

An upper mixing zone (210) and a lower mixing zone (214) are supplied with hot air through a radiator (203) and with cold air by means of respective bypass ducts (205, 208). Respective mixing dampers (212, 219) make it possible to separately adjust the temperature in the two mixing zones, from which treated air is sent to different parts of the vehicle cabin. According to the invention, the two bypass ducts (205, 208) pass below the radiator (203), which makes it possible to minimize the length of the hot air path between the radiator and the defrost outlet duct (221) located at the upper part of the housing (200) of the installation, and consequently to accelerate defrosting or defogging of the windshield required urgently for safety reasons.