In general, this disclosure describes example techniques for a flexible heater system to automatically configure itself to operate over different input supply voltages. The flexible heater system may include a flexible heater that includes a first heater element and a second heater element. The flexible heater system may also include a switch circuit that may automatically couple the first heater element and the second heater element in a first configuration when an input supply voltage is at a first voltage level. The switch circuit may also automatically couple the first heater element and the second heater element in a second configuration when the input supply voltage is at a second voltage level.