Systems and methods of heating an accurate quantity of a fluid. A determination is made that an event in which a relatively large quantity of hot water is used has occurred. One or more temperatures are sensed. An increase in a temperature set point is made if the sensed temperatures indicate a shortage of hot water for the event. A decrease in the temperature set point is made if the sensed temperatures indicate an excess of hot water was available for the event. No change is made to the temperature set point if the quantity of hot water available for the event was appropriate.