Abstract: Electrical resistance heating elements are provided which are useful in heating fluid mediums, such as air and water. The heating elements include an element body having a supporting surface and a resistance wire wound onto the supporting surface which is connected to a pair of terminal end portions. Disposed over the resistance wire, and over most of the supporting surface, is a thermally-conductive polymeric coating which hermetically encapsulates and electrically insulates the resistance wire from the fluids to be heated. This thermally-conductive polymer coating has a thermal conductivity value of at least about 0.5 W/m .degree.K. Improved properties are preferably provided by ceramic powder, such as Al.sub.2 O.sub.3 and MgO, and glass fiber additives.

Abstract: Electrical resistance heating elements, hot water heaters containing such elements, and methods of preparing such elements are provided. The electrical resistance heating elements of this invention can be disposed through a wall of a tank for heating fluid, such as water. They include a skeletal support frame having a first supporting surface thereon. They also include a resistance wire wound onto the first supporting surface and preferably connected to at least a pair of terminal end portions. The support frame and resistance wire are then hermetically encapsulated and electrically insulated within a thermally-conductive polymeric coating. The skeletal support frame of this invention improves injection molding operations for encapsulating the resistance wire, and can include heat transfer fins for improving thermal conductivity.