US Patent 7822325 Water heater and method of customizing the water heater

A water heater including a vessel, a heating fixture (e.g., an electric-resistance heating element, a gas burner) having a rated maximum heating output, and a controller. The controller includes an interface and a temperature sensor. The controller can control the heating output of the heating element based on a sensed temperature of the temperature sensors. The heating output is a defined maximum heating output for the heating fixture. Also disclosed are methods of defining the capabilities of a water hater heater and methods of operating a water heater.