1. A water heater system, comprising in combination: a tank for holding water; at least one heater for heating water in the tank; and a controller, wherein the controller calculates a minimum temperature setpoint of the at least one heater as a function of both a current user setting and a minimum temperature setting, wherein the current user setting is a temperature value that is input by the user, and wherein the function comprises increasing the minimum temperature setpoint as the current user setting is increased, thereby establishing the minimum temperature setpoint as the minimum water temperature, wherein the controller adjusts the minimum temperature setpoint of the at least one heater based on the following equation: 
 SP min =Knob min +(Knob current −Knob min )/2 where SP min is the minimum temperature setpoint; Knob min is the minimum temperature setting; and Knob current is the current user setting.