Radiant heater having multiple heating zones

In a radiant heater having multiple heating zones there is provided a first heating zone (8) incorporating at least one heating element (16, 18) and a second heating zone (10) incorporating at least first and second heating elements (20, 22). A thermal cut-out device (14) includes a temperature sensor (24) which passes through at least the first heating zone (8) and which is responsive solely to heat emitted in the first heating zone. A manually operable switch (40) permits switching between first and second heating states. In the first heating state, the at least one heating element (16, 18) in the first heating zone (8) is energised alone, while in the second heating state the at least one heating element (16, 18) in the first heating zone is electrically connected in series with the second heating element (22) of the second heating zone (10), the at least one heating element and the second heating element being energised in parallel with the first heating element (20) of the second heating zone.