In vehicles using a typical heating, ventilating, and air conditioning (HVAC) unit, ventilation loss through the cabin accounts for more than 60% of the heating load. This fact has increasingly important because of the low heat source characteristics of today's increasingly efficient engines. In response to this trend, a new type of air conditioning system, a “Two layer flow HVAC unit”, has been developed. This unit sends low humidity fresh intake air to the window neighborhood in order to promote good demist performance and warm recirculated air to the occupant foot area for increased efficiency. With this system, it is possible to reduce the ventilation loss by half and to raise the cabin temperature by 5°C.