An economically operated, dual-energy hot water supply system. The system includes a first heat source of a first type and a second heat source of a second type different than the first type. The system also includes a controller. The controller determines a first energy consumption of the first heat source to generate a unit heat, determines a second energy consumption of the second heat source to generate the unit heat, compares a first power cost of the first heat source with a second power cost of the second heat source, the first power cost being based on the first energy consumption and the first price, the second power cost being based on the second energy consumption and the second price.
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