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How Long Do Solar Panels Last?

Many residential solar companies offer a 25-year warranty, guaranteeing that the system will produce a certain power output during that time. Many people assume the panels will no longer work reliably after that period. But is this assumption correct?

A 25-year lifespan is a safe, conservative estimate — that’s why our solar calculator uses this figure for projections. It provides homeowners with a reliable baseline for planning and expected savings.

But what if solar panels actually last longer? Recent research suggests they do.

According to a 2020 report from the Berkeley Lab, solar experts "have increased project-life assumptions over time, from an average of ~21.5 years in 2007 to ~32.5 years in 2019." This represents a 50% increase in projected lifespan in a little over a decade. Many experts now expect today's panels to last 35 years or more.

The financial implications are substantial. An additional five or ten years of operation could generate tens of thousands of dollars in extra savings, making a residential solar investment even more valuable than initially projected.

The SunWise calculator continues to use the conservative 25-year baseline because warranties provide a guaranteed minimum. We also factor in a 0.5% annual degradation in panel output — another safety measure designed to give you confidence in your investment. Yet, many experts anticipate that residential solar systems will deliver even greater returns over their full operational lifespan.

Of course, it’s always wise to consult a qualified financial advisor before making any major purchase. They can help you take account of warranties, expected lifespan, and other factors to make the best decision for your home and your personal financial situation.

Reference: "Benchmarking Utility-Scale PV..."