The hand-held induction air-cooled induction heater used for heating of metallic mechanical or decorative objects to facilitate their removal or installation contains a high frequency inverter operating in voltage or current resonant mode, including power semiconductor switching device(s) having turn-on or turn-off delay time, circuitry to control the timing of on and off periods of said switching device(s), the circuitry having delay time, wherein the threshold voltage or current reference to initiate commutation or timing is not zero, and is dynamically varied in response to the instantaneous input inverter supply voltage and/or inverter frequency to achieve switching device(s) heating or dissipation reduction resulting from improved commutation timing of said power switching devices.