A water heater including a water inlet line having an inlet opening that
introduces cold water to a tank, a water outlet line having an outlet
opening that withdraws heated water from the tank, and a heating element.
The water heater further includes a control circuit. The heating element
can be an electrical resistance heating element, a gas heating element,
or a combination thereof. In one construction, the gas heating element
includes a first combustive section and a second combustive section
separately controlled from the first combustive section.