The heating device has a reactor with a catalytic burner and a radiation burner (15) between a fuel gas/combustion air collection space (4) and an exhaust line. The catalytic burner is provided by a block (3) of copper or copper alloy, provided with hollow spaces (10) filled with catalytic coated particles between the collection space and the radiation burner. A layer (14) of a porous material, e.g. a ceramic foam, is provided between the block and the radiation burner.
