599364 Disclosed is an electrically heated smoking system for receiving an aerosol-forming substrate (407). The system includes at least one heater for heating the substrate (407) to form the aerosol, and a power supply for supplying power to the at least one heater. The heater has a plurality of electrically conductive tracks (403) on an electrically insulating substrate (401) and the electrically insulating substrate (401) is rigid and is arranged to be inserted into the aerosol-forming substrate (407). The electrically conductive tracks (403) have temperature coefficient of resistance characteristics such that the electrically conductive tracks (403) can act as both a resistive heater and as a temperature sensor.