A method and apparatus for improving the performance of a regenerative burner has a combustion chamber which receives and combusts controllable amounts of auxiliary fuel, an oxidizing gas, and possibly air to form hot combustion products. A controllable amount of a main fuel is then delivered to the combustion chamber and is pyrolyzed by the hot combustion products to produce a hot flame. By controlling the flame, one can maintain optimal temperature of the combustion air passing through the flame. Sensing means and computing means allow for automatic adjustments of fuel, oxygen and air flow to further maintain optimal combustion air temperatures.