The solar payback period is the time needed for bill savings and export earnings to recover the system’s net upfront cost. It depends on the purchase price, available STC discount, electricity rates, feed-in tariff, system output, household usage and whether you add a battery. A qualified installer can provide an estimate using your roof, location and electricity data, but actual results may vary as energy prices and usage change. Compare the estimate with current information from the Clean Energy Regulator and your energy retailer.