Abstract: A method for enhancing combustion efficiency and reducing harmful emissions of any furnace fueled by coal or other carbonaceous fuels includes the steps of providing a high-output electrolyzer assembly which includes spaced-apart stainless steel plates submerged in an electrolytic bath. A voltage is applied between the plates and sufficient electrical power is supplied to generate a desired production of hydrogen and oxygen gases. Those gases are captured and directed directly into the combustion air intake of the furnace. Gas flow is controlled, primarily, by varying current flow and electrolyte concentration in the electrolyzer unit. The method differs from those of the prior art in its simplicity in that the oxyhydrogen gas is captured and directed directly into the combustion air intake of the furnace without the use of gas storage tanks, pressure regulators, mass flow controllers, or any other costly control equipment.