The air conditioning system regulates temperature air outlet by mixing cold and warm air in an appropriate ratio. The heater core and evaporator core are installed in the heater unit that has the air mix control damper and the mode control damper. The blower unit is composed of a blower motor, the recirculation control damper and the dust and pollen filter. The blower unit is connected to the heater unit by the duct integral with the blower unit.