The payback period is how long it takes for the money a solar system saves to add up to its net cost after incentives. It depends on the price you pay, the incentives you can actually use, your electricity price and how it changes, your utility's export credit, your roof's output and any financing costs. A shorter payback is better, but it is not the whole picture: total savings over the system's life, the risk of rate-plan changes and the cost of replacing an inverter also matter. Our estimates show the year cumulative savings first exceed the net cost for a cash purchase. A loan's interest stretches the effective payback, which the calculator shows separately.
Related terms and pages
- Price per watt: Total installed price divided by system size in watts: the fairest way to compare quotes.
- Degradation rate: How much a solar panel's output declines each year as it ages.
- Self-consumption: The share of your solar output you use in your home as it is produced.
- Estimate your payback