Abstract: A thermal-insulating panel for use in an electric furnace. A refractory fiber mat is formed of discrete refractory fibers bonded together by an inorganic bonding agent having a hot face, a cold face and a plurality of side faces. A plurality of individual ceramic supports are partially embedded in said mat and protrude outward from the hot face. The embedded portions are shaped so as to be firmly anchored within the mat, and the protruding portions are shaped to support an electrical resistance heating ribbon in the interior of the furnace.The modules are preferably formed in a felting box where the ceramic supports extend horizontally from cavities in the front wall. The layers of fibers build up upon the bottom screen in planes perpendicular to the hot face of the module.