Abstract: An electric heating device includes a flexible resistor ribbon, a plurality of sections of electroconductive coating attached to the resistor ribbon at preset intervals, and connector contacts coupled to the resistor ribbon for enabling connection of a power source to the resistor ribbon. The resistor ribbon has a high specific impedance. The flexible resistor ribbon is attached to a rigid or flexible flat base panel for incorporation into a building as a floor, wall or ceiling panel. Layers of electric insulation are attached to the base so as to sandwich the flexible resistor ribbon. Where the resistor ribbon is bent back on itself, for example, to form a snaking configuration, a strip of two-sided adhesive tape is attached to the layers of electric insulation and to the ribbon at multiple spaced points.