Abstract: A high efficiency fast recovery electric fluid heating system includes a closed elongated housing having thermostatically controlled high-wattage electric immersion heating elements extending from the housing ends into the interior thereof. The housing is adapted to be filled with fluid to be heated by the heating elements and has a fluid inlet at one end and a fluid outlet at the other. A helical tubular member extends within the housing from end to end thereof in coaxial spaced relationship to the heating elements and has its ends extending externally of the tank to provide inlet and outlet connections for supply of fluid thereto. An elongated open-ended tubular member is disposed within the helical tubular member and around the heating elements to define a confined fluid heating space within the housing.