Abstract: This invention relates in general to a renewable energy water heating system and method for residential and commercial applications. The heating system has a renewable energy source providing a DC electric current and a controller connected to the renewable energy source. The water heater is connected to the controller, the water heater having a water storage tank and at least one heating element for heating water in the tank responsive to an electric current supplied thereto. The controller modulates and switches the DC electric current to produce a converted output to provide the electric current to the at least one heating element to heat the water.