How long do solar panels last?

Do solar panels degrade over time?

The short answer: Yes, solar panels degrade over time. As with most technologies, power ebbs as the years go by. Degradation takes place when the power output grows smaller — but what influences this reduction, and how does it impact your system?

Causes of degradation

There are three main sources of degradation: age, light and voltage leaks. Of these, time is the biggest reason behind energy loss. After enduring weather conditions and other outdoor wear, the panels begin to corrode.

Most solar panels operate at about 90% output after 20 years of use.

Strangely enough, light also plays a role in both feeding and draining the solar panel system. Light degradation occurs within the first few weeks of installation, but companies can install ultraviolet (UV) blockers to protect the solar cells from extreme radiation.

When different parts of the panel operate at various voltages, leaks can occur. The leaks result in black cells — in other words, defunct cells can reduce overall functioning by up to 30%. Since this is the least common cause of degradation, it’s unlikely that you’ll experience this problem directly.

At the end of the day, if you have certified parts, proper installation and good maintenance habits for your solar panels, you shouldn’t experience extreme degradation.

Measuring solar panel degradation

According to research by the National Renewable Energy Laboratory (NREL), the average degradation rate is 0.5% for solar panels — i.e., your solar output should be about 90% of its original output after 20 years. People frequently choose to replace panels at this point, but some monocrystalline and polycrystalline panels can reach 30 years of age.

“[Solar panels] don’t require fuel, save photons blasted from outer space,” Alex Blackmer, CEO of Solaris Energy and executive director of The Atmosphere Conservancy, told us. “There are no moving parts. It’s just electrical and chemical connections, so as long as ... the channels that the electricity moves on are intact, they work. There’s nothing to wear out in terms of mechanical parts.”

Impact of degradation

The more solar panels degrade, the higher energy losses you’ll experience. That could mean heftier utility bills since you’ll have to draw more energy from the grid. If you're neither connected to the grid nor have a backup home battery, it may result in a power outage in your home.

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Solar panel life span

Companies build solar panel systems to fit a home’s specific needs. This means a system’s life span may vary below or beyond the standard 25 years. What type of solar panel you install, the weather conditions in your area, the angles of the panels and other factors can impact your power usage.

Blackmer used his own house as an example of just how much life you can get: “I bought used solar panels when I built my house,” he said. “They were first-generation, commercially available panels — 10 years old at the time. They’re totally antique now. I bought them in 1995 and they’re still on my house producing electricity in 2023.”

He continued: “There’s a degradation process for sure — we calculate a half a percent of year of degradation when we calculate economic returns from an array,” Blackmer stated. “So half a percent every year over 38 years is 15% to 18% degradation. That’s not very much.”

Factors that affect life span

Wind speed not only plays a role in turbines; it also has a place in solar radiation. Strong gusts allow the panels’ surfaces to maintain cooler temperatures and therefore experience greater longevity.

Climate also factors into whether your panels hit a 25-year milestone. Regions of extreme heat can damage the solar cells and decrease output over time, and high humidity can put a strain on the panels. In general, cooler, dryer areas tend to have more long-lasting panels.

Another factor to consider: At what angle are your panels installed? The optimized mounting position for your panels depends on your location, and a well-calculated angle keeps your system running strong.

Longevity by type of solar panels

When on the hunt for solar panels, you’ll likely come across three types: monocrystalline, polycrystalline and thin-film.

Constructed out of the highest-grade silicon, monocrystalline and polycrystalline remain in competition for the longest life span. While monocrystalline is less productive in cold weather, polycrystalline is more sensitive to heat.

Because thin-film panels are less affected by temperature and prices, they’re a common choice for companies — homeowners, however, tend to bypass this option because these panels don’t usually stay in great condition for long.

Research shows crystalline panels are the most dependable in the industry. They beat out other designs on fire, hail and hurricane tests.

» LEARN: Types of solar panels

How to make your solar panels last longer

There are several steps you can take to ensure you’re getting the most bang for your buck when it comes to your solar panels’ longevity. As long as you keep them clean, keep track of performance and repair problems in a timely manner, your energy source should last a long time.

Regular maintenance and cleaning

In order to work properly, solar panels need to absorb the sun. Naturally, they can’t do that when covered in dirt, twigs or other yard debris.

If you get in the habit of scrubbing pollen and bird droppings off your panels, they should work at maximum capacity. If you notice a lag or other concerns, consider hiring a professional cleaning service to get the job done.

Quick tips for making your panels sparkle include:

• Use a biodegradable soap and a soft rag.
• Avoid abrasive materials and rough sponges so you don’t scrape the glass.
• If the dirt isn’t too thick, run a hose over the panels to rinse the worst of it off.
• Buy a solar panel cleaning kit that includes longer hand-held wipers so you don’t have to climb on the roof.

Blackmer adds that, apart from direct damage, solar panels are pretty tough: “They put this stuff on satellites and shoot them into space,” he said. “They just keep working.”

» MORE: Solar panel cleaning

Monitoring for issues

Your solar panels’ health depends on their meters, inverter and a handful of other parts running at top efficiency. You’ll know when the system is malfunctioning or losing steam — it should be reflected in your utility bills and power supply. Make sure to call a professional immediately when you experience electrical problems. Letting an issue fester may affect your solar panels’ life span.

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Common problems you want to be on the lookout for include inverter issues, wiring damage, circuit break trips and mechanical damage. If your house undergoes an energy plummet, it likely has to do with the panel’s inverter, which converts light from a direct current to an alternating one.

Wind and mice can also cause wear and tear on wires, so check to ensure the cables are intact and in their correct places. If these actions don’t fix the issue, the circuit breaker is your next best bet. When this part is worn down, it can be a major safety concern.

Upgrading parts

Your solar panel system is unique, so if you aim to upgrade or replace malfunctioning parts, it’s a good idea to stick with your original installer. But when exactly should you give your panels a tuneup? For the panels themselves, you can exchange them once microcracks appear. Just note you’ll need to match the identical wattage and dimensions, among other specifications, so your system continues to function accurately.

Another option is to upgrade your inverter, especially if it’s a string inverter rather than a microinverter. The former lasts only about 10 to 15 years, compared with the latter’s 25. As long as the replacement falls within the warranty period, you shouldn’t have to pay out of pocket. You may run into a roadblock if original models are out of circulation, but you should still be able to track down new parts with the same specifications.