Abstract: A heater including a generally cylindrical shell defining its housing arranged in a very closely spaced relation to the outer periphery of its combustion chamber assembly and its fan device as it bounds a plenum chamber therebetween. The combustion chamber assembly has its discharge end adjacent the discharge end of the shell. The relative configuration of the outer peripheral surface of the combustion chamber assembly and that of the discharge end portion of the shell creates therebetween a passage through which the fan device, on energization thereof, produces a very high velocity flow of a thin layer of air which, on discharge, is throttled and abruptly and sharply driven into the center of the flow from the assembly. The effect of this is to moderate and influence a relative uniformity of the temperature of the discharge and rapidly project it outwardly of and considerably beyond the heater.