A heating system (100, 900) comprising: a cavity (110, 960) configured to contain a load; a thermal heating system in fluid communication with the cavity, wherein the thermal heating system is configured to heat air; and a radio frequency, RF, heating system that includes an RF signal source configured to generate an RF signal, one or more electrodes(962, 966) configured to receive the RF signal via a transmission path, a variable impedance matching network electrically coupled along the transmission path between the RF signal source and the one or more electrodes, the variable impedance matching network comprising at least one variable component, and a system controller configured to execute instructions for: monitoring impedance state of the variable impedance matching network, identifying, based on the monitored impedance state, that a change point has occurred at a change point time and corresponding to a change point state during a heating operation, the change point state corresponding to a first impedance state value of the variable impedance matching network at the change point time, automatically identifying completion of the heating operation based on the first impedance state value, and automatically taking an action in response to identifying completion of the heating operation; wherein the system controller is further configured to execute instructions for: determining an estimated load mass based on the change point state, wherein automatically identifying completion of the heating operation is further based on at least the estimated load mass. a cavity (110, 960) configured to contain a load; a thermal heating system in fluid communication with the cavity, wherein the thermal heating system is configured to heat air; and a radio frequency, RF, heating system that includes an RF signal source configured to generate an RF signal, one or more electrodes(962, 966) configured to receive the RF signal via a transmission path, a variable impedance matching network electrically coupled along the transmission path between the RF signal source and the one or more electrodes, the variable impedance matching network comprising at least one variable component, and a system controller configured to execute instructions for: monitoring impedance state of the variable impedance matching network, identifying, based on the monitored impedance state, that a change point has occurred at a change point time and corresponding to a change point state during a heating operation, the change point state corresponding to a first impedance state value of the variable impedance matching network at the change point time, automatically identifying completion of the heating operation based on the first impedance state value, and automatically taking an action in response to identifying completion of the heating operation; wherein the system controller is further configured to execute instructions for: determining an estimated load mass based on the change point state, wherein automatically identifying completion of the heating operation is further based on at least the estimated load mass. an RF signal source configured to generate an RF signal, one or more electrodes(962, 966) configured to receive the RF signal via a transmission path, a variable impedance matching network electrically coupled along the transmission path between the RF signal source and the one or more electrodes, the variable impedance matching network comprising at least one variable component, and a system controller configured to execute instructions for: monitoring impedance state of the variable impedance matching network, identifying, based on the monitored impedance state, that a change point has occurred at a change point time and corresponding to a change point state during a heating operation, the change point state corresponding to a first impedance state value of the variable impedance matching network at the change point time, automatically identifying completion of the heating operation based on the first impedance state value, and monitoring impedance state of the variable impedance matching network, identifying, based on the monitored impedance state, that a change point has occurred at a change point time and corresponding to a change point state during a heating operation, the change point state corresponding to a first impedance state value of the variable impedance matching network at the change point time, automatically identifying completion of the heating operation based on the first impedance state value, and automatically taking an action in response to identifying completion of the heating operation; wherein the system controller is further configured to execute instructions for: determining an estimated load mass based on the change point state, wherein automatically identifying completion of the heating operation is further based on at least the estimated load mass.