The payback period is the amount of time it takes to pay yourself back. If you pay cash or make a down payment on a loan, the payback period would be the amount of time it takes you to cover that upfront investment with monthly savings. For instance, if you pay $10,000 in cash for your system and your monthly savings from going solar is $100, the payback period would be 100 months or 8.33 years.

Your payback period will be 0 years if you have a mortgage with no down payment, PPA, or lease on the equipment since there are no initial costs to recover.