Abstract: A hot water heater for generating substantial instantaneous hot water by positioning a plurality of burners adjacent one end of a heat transfer section. The heat transfer section includes an elongated housing which has a plurality of tubes carried therein. Water is circulated through the elongated housing for being heated by the products of combustion being generated by the burners being drawn within the elongated tubes by means of a vacuum. A combustion chamber in which the burners are carried is frusto-conical in shape with the large diameter end being exposed to the atmosphere and the small diameter end being in communication with the heat transfer section.