A heating device comprises a heater having a first surface and a second surface, with the second surface being generally opposite of the first surface. The heater is configured to receive an electrical current and convert it to heat. The heating device additionally includes at least one heat transfer assembly positioned along the first and/or second surface of the heater. In one embodiment, the heat transfer assembly includes a plurality of fins that generally define a plurality of fin spaces through which fluids may pass. In some arrangements, the heating device comprises an outer housing that at least partially surrounds the heater and one or more of the heat transfer assemblies. Heat generated by the heater is transferred to the fins of the heat transfer assembly. In addition, fluids passing through the fin spaces are selectively heated when electrical current is provided to the heater.