A method and heating device for heating a liquid, particularly useful for removing liquid condensate from cooling devices, by wetting a heating plate with the liquid and controlling the electrical power supply to maintain the heating plate at a the predetermined temperature above the boiling point of the liquid, such that when the heating plate is not wetted by the liquid, the electrical power supply to the heating plate is automatically maintained at a relatively low value, but as soon as the heating plate is wetted by the liquid, the electrical power supplied to the heating plate is automatically increased until the liquid is completely evaporated. The heating plate is heated by one or more PTC thermistors in which the electrical resistance increases with temperature to automatically maintain the predetermined temperature. Besides evaporating liquid condensate, the heating device is described for use in many other applications including steam generation, space heating and plastic molding.