The disclosed technology includes systems and methods for operating a pool water heating system. The pool water heating system can include a heat pump, a supplemental heat source, a water temperature sensor, and a controller. The controller can be configured to receive water temperature data and, in response to determining that the temperature of the water is less than a threshold temperature, output a control signal to activate the heat pump. The controller can further determine an expected heating time that can be indicative of an amount of time required for the temperature of the water to be greater than or equal to the threshold temperature. The controller can also generate a heating schedule based at least in part on the expected heat time and a predetermined time of use. The heating schedule can be indicative of a heat pump operation time and a supplemental heat source operation time.