How long do solar panels last?

Long story short, a solar panel’s lifespan is about 25 to 30 years. Its performance naturally declines over time, eventually rendering its “useful life” complete.

Here’s where it gets complicated: Just because a solar panel's “useful life” ends doesn’t mean it's necessarily useless. Solar panels can still produce electricity well into their “afterlife,” but the 25 to 30-year benchmark is usually the point at which investing in a new system makes more practical and financial sense. 

Ultimately, your solar panels’ lifespan depends on several factors: Your installer’s handiwork and integrity, your specific equipment and its warranties, degradation rates, and your maintenance routines.

A solar panel’s lifespan isn’t measured by when it stops producing electricity entirely. Instead, we use its “useful life” to determine its lifespan, which is about 25 to 30 years. 

Solar panels slowly degrade and produce less and less electricity over time. Older solar panels can be useful for small applications with low electricity demands, but most people retire their solar panels after about 30 years. By that point, energy production has typically declined significantly enough that it makes sense to replace them with a newer, higher-performing system (not to mention that most warranties end at that time).

A 2021 study by the National Renewable Energy Laboratory (NREL) found that, on average, solar panel output falls by 0.5% to 0.8% each year. This rate of decline is called the solar panel degradation rate. 

The degradation rate of your solar panels tells you how much electricity you can expect them to produce in any given year of their useful life. To determine the projected output of your solar panels, multiply the degradation rate by the number of years since installation and subtract that number from 100%.

For example, a 0.8% degradation rate means that in year two, your panels will operate at 99.2% of their original output; by the end of their 25-year useful life, they will still be operating at 82.5%. A slightly more durable panel with a degradation rate of 0.5% will likely produce around 87.5% of its original output in year 25. 

Solar panel degradation rates are constantly improving as solar panel technology improves. Degradation rates below 1% are now standard throughout the industry, but premium manufacturers like Maxeon offer rates as low as 0.25%.

Solar panel warranties are key to maximizing the lifespan of your solar panel system. In addition to your equipment warranty, which certifies against manufacturing defects, your performance (AKA power) warranty guarantees that your solar panels maintain a certain percentage of their original output each year. This can help you understand the anticipated degradation rate of your solar panels. 

Here's a breakdown of some of the top performance warranties offered by solar panel manufacturers available through the EnergySage Marketplace:

Solar panels are generally very durable. Most solar panels are designed and tested to withstand the elements like hail, high winds, and heavy snow loads. And thanks to their lack of moving parts, solar panel systems usually require little to no maintenance. Still, maintaining your solar panels can boost production. 

Here are a few actions you can take to get the most out of your solar panels: