How long do solar panels last

By far the most popular question we get asked after how much do they cost and how much will I save is “How long do solar panels last?

Solar panels lose about half a percent a year in efficiency. With a warranty of  25 years most panels will only lose about 12.5% of their original power. The panel still retains 87.5% power output, that’s only 12.5% less power than when it was originally tested. After 25  years, a 10 KW system is now a 8.75 KW system, and a 4 KW system is now effectively an 3.5 KW system. When looking at these numbers it’s easy to see why solar panels are such a great long term investment.

Unlike many other consumer products, solar panels are not designed to break as soon as the warranty ends. Panels will continue to produce clean electricity, although at a slightly less efficiency each year. Some decidedly old-school solar panels tested have been producing electricity daily for about 40 years or so, and are expected to continue to power homes and businesses for decades more.

It’s also important to note that not every panel tested saw degradation rates as high as 0.5%, some on the older panels are still performing in line with their original specs, even after decades in the sun. Weather and temperature conditions play an important part of how a panel’s output degrades. It’s good to know that even in a worst case scenario your still only losing about .5% per year per panel on average.

The decades-long life span of solar panels makes the economics of going solar one of the best investments you can make in terms of ROI over time, as most systems will pay for themselves within the first seven years, and will produce many decades of clean electricity for their owners. The cost of electricity will most likely continue to rise at a rate of more than .5% per year so no matter how old your panels get you will still be staying way ahead of the curve in terms of monthly savings on power.