Abstract: Techniques for solar panel wattage determination are provided. A computing device can determine a potential wattage output of a candidate solar panel array using insolation data for a corresponding geographic region, and determine potential energy consumption for a property of a utility customer in the corresponding geographic region using usage data from the property. The computing device can adjust a size of the candidate solar panel array to vary the potential wattage output, and apply a different rate plan to the potential energy consumption for each adjustment to the potential wattage output. The computing device can determine that one of the wattage output adjustments yields a cost efficiency metric that is less than a predetermined threshold. In turn, the computing device provides a notification of the candidate solar panel array corresponding to the cost efficiency metric being less than the predetermined threshold as a recommendation to the corresponding utility customer.