Abstract: To supply heat to the passenger compartment of an automobile car body immediately upon entering it, an approximately triangular housing has two branch outlet ducts converging from the opposite ends of a main inlet cross duct including a fan chamber containing a reversible electric fan. This fan initially draws cold air into the fan chamber of the main inlet cross duct and forces it through an electric heating coil and then through one of the two converging branch outlet ducts to a common outlet containing a freely pivoted damper which in response to the pressure of the forced air swings to cut off air flow from the other converging branch outlet duct and at the same time directs the heated air through a horizontal transverse duct into the passenger compartment.