Panel (10) for generating and diffusing heat obtained from a heat-radiating board (30) comprising one or more pieces of electrothermal fabric, with strips of fibreglass laid side by side to form the warp, the weft (50) consisting of a continuous copper wire (51), small in diameter and of considerable length, coated with insulating material, that extends serpentinewise passing alternatively above and below the strips of fibreglass, said board (30) being completed by intermediate and external layers (35, 36) of epoxidic thermoadhesive material and clad on both surfaces with sheets of micanite (31, 32), so that on connecting the ends of the wire (51) forming the weft (50) to a source of electric current, boring holes (65, 66) using means, that may be a laser beam, on the thermoadhesive layer (35, 36) covering the weft (50), this latter converts electric energy into thermal energy.