a radiant electric heater for use in a smooth top cooker includes a base of electrical and thermal insulating material and two heating elements supported on the base . one of the heating elements is energisable independently of the other element , for example to permit the heater to be adapted to different size cooking utensils . a peripheral wall of thermal insulating material extends laterally around the heating elements and a dividing wall is arranged between the heating elements such that , in use , separate and distinct heating zones are formed on the smooth top of the cooker . the dividing wall is received in the base of electrical and thermal insulating material and is retained in the base by friction . the dividing wall may additionally be constructed and arranged as a barrier effectively only to thermal convection currents generated in the heater .