Radiant element, usable in at least one furnace for heat treatment, and/or for continuous galvanizing and annealing lines of sheet metal strips or plates and/or other products made of steel and/or other metals and/or for the modernization of at least one pre-existing furnace, wherein the radiant element is used to emit and/or radiate heat, wherein the radiant element has a main longitudinal extension (L) and a transversal extension (M), perpendicular to the main longitudinal extension (L), and includes a shaped wall which defines an external surface, an internal surface and an internal cavity, in addition to at least two main hollow seats, adapted in use to house at least one heating means and at least one connection seat; radiant system and use of this radiant element.