Some installers will calculate this for you, but the answer depends on the assumptions they make. If you use only about 30% of the electricity you produce it could be 20 years. This would reduce to about 15 years if you heat water with excess electricity, or if you secured a reasonable SEG payment, and would reduce further if you did both If you also install a battery and maximise the benefits of storing your generated electricity and off-peak grid electricity, this could drop to 10 years. This is based on electricity prices and solar PV prices in early 2022 changes in these prices affect the payback period. More info in the financial calculations below.