A method for generating heat includes passing a liquid between electrodes connected to an alternating current power supply. The liquid must have a sufficient level of electrolytes or dissolved minerals so as to be effectively heated. The level of current applied to the electrodes is preferably monitored and controlled. Exothermic, electrochemical reactions occur within the liquid and at the surface of the electrodes. More particularly, the electrodes are comprised of a material that can be oxidized, and the oxidation process during operation of the heater supplies additional current to heat the liquid.