Abstract: Our invention relates to open coil electric heating elements of conventional construction but treated to resist corrosion and to electrically insulate exposed metallic surfaces. In accordance with the invention, the component parts of the heater, except the coiled resistance wire and in some cases the supporting insulating bushings, are assembled and then coated with a silicone resin-based coating composition. The composition is applied in a flowable state to cover all exposed surfaces and fill all cracks and crevices to thereby prevent accumulation of moisture thereat.