The Real Answer to the Question, “How Long Do Solar Panels Last?”
If we could capture just one hour’s worth of solar energy that hits the Earth each year, every gallon of oil, every lump of coal, and every cubic foot of natural gas could be left in the ground.
The cost of solar panels has fallen 99% since 1977, making solar energy more accessible to a lot of people. However, for many homeowners, a solar panel array is still a significant investment, even with net metering, and federal rebates.
Which is why a question that I often hear is how long do solar panels last and what can be done to increase their service life.
Basically we’ve learned to make [solar] modules cheaper a lot faster than we’ve learned how to install them cheaper. Now the module is only a small fraction of the total price.
Zach Holman, Assistant Professor of Electrical Engineering, Arizona State University
How Long Do Solar Panels Last?
Solar panels last about 20 years, according to the Federal Trade Commission.
But there’s much more to the answer than that.
The exact number would depend on several factors, like the type of the panel, the way the system is installed, the climate where you live, and the maintenance.
The great news is that, with proper maintenance, your panel may actually run for as long as 40-50 years. Read on to know how you can make your panel last as long as this.
What is the Solar Panel Degradation Rate?
The solar panel degradation rate on average is 0.5% per year.
This is the rate at which your panel efficiency reduces over time.
Basically, it shows the quality of your panel — the smaller the rate, the longer your panel will keep its properties.
A degradation rate of 0.5% per year means that, after a standard 25-year long warranted service, your solar panel system will provide 87.5% of its factory output.
Manufacturers like SunPower, however, have achieved degradation rates that are as low as 0.3% per year. This means that after 25 years, your panel will operate at 92.5% of its original output.
Not too shabby for something that gives you free energy.
5 Tips on How to Make Your Solar Panels Last Longer
One of the things that friends and colleagues who are interested in solar energy almost always ask me is this: Is it possible to make solar panels last longer?
And my answer is always yes, it’s definitely possible to make solar panels last longer. You can achieve this by doing these 5 things:
1. Regularly Get Your Panels Checked And Maintained
Broken glass, cracked panels, and loose connections are the top three issues you can have with your panels over the years.
Electrical faults are more difficult to discover, but if you suspect something is wrong with your solar system, have the company check your power output.
If you see a large difference from the same month in previous years, you might be dealing with an electrical issue.
2. Replace Inverters After 10 Years
Faulty inverters cause system failures much more often than the panels themselves. A typical solar inverter has a lifespan of 10-15 years, with 5-10 years of warranty.
This means that you’ll need to replace the inverter much sooner than your panels. These days, many homeowners choose microinverters, because they can last for 25 years — almost as long as quality panels.
3. Maintain And Replace Batteries
If you have a large bank of batteries, rotate them periodically. This is so that each battery will receive an equal amount of charge, which will extend its service life.
You can also improve their charging by using large battery cables, which have lower resistance.
Lastly, never leave your batteries uncharged for longer periods of time, as this can reduce their capacity.
4. Keep Your Panels Clear Of Debris And Other Materials That May Damage It
Although quality solar panels are built to endure high winds, heavy snow loads, and even inch-sized hail falling at about 50 miles per hour, you still need to keep them clean at all times. 
It’s also always better to wash them off in the morning before they heat up, so they don’t crack.
Your solar panels will last longer and operate at their peak efficiency if you also regularly remove dust, leaves, pollen, and bird droppings from them. Check out the video below to see how you can do this.
5. Work With A Trustworthy Solar Panel Provider
Probably one of the best things you can do to make your solar array last longer is to get a reliable provider at the very start. Two of the most popular and trustworthy ones in the industry are SunPower and Jackery.
After 35 years of experience, SunPower has perfected solar panels with an expected service life of 40 years.
Now, if I’m about to make an investment that will keep my home running on free energy, I’d go with the technology that lasts.
Take it from Christer Rygaard himself. A solar installer, he tried installing 39 conventional n-type solar panels on his own home and a similar set of SunPower panels on his neighbor's house to see how they would stack up against each other.
After a year he noticed that his neighbor's system generated 12% more energy.
Now this may not seem much, but if you ask me, just think how much more his neighbor will save as compared to him over the course of 25 years.
If you want to know how much you can save with solar power, you should check out SunPower’s solar savings estimator to get a free estimate of your home’s solar energy potential.
Founded by a former Apple battery engineer, this company relies on formidable R&D and manufacturing expertise to offer eco-friendly portable power products, like this one.
If you’re an outdoorsy person, you’ll find their SolarSaga 60W Solar Panel to be just the thing you need when you decide to go off the grid.
With this portable solar collector, you can power your phone, tablet, and every other gadget wherever you go. You bet I wish I had one of these when I was a kid.
THE JACKERY SOLARSAGA 60W
What I liked the most about this system is its weight and flexibility. I like to travel light whenever I go hiking or camping, and this 4 lbs solar generator folds and zips like a laptop sleeve.
If you’re like me, you can just slide it into your backpack and go into the wild. Ever asked yourself how Bear Grylls charges his camera?
I’ve also found the sturdier SolarSaga 100W Solar Panel to be a great addition to the outdoors kit I keep in my car.
For me, the real prize was when I discovered how easily I can use it to power my phone, fitness tracker, and a USB reading light on my boat.
THE JACKERY SOLARSAGA 100W
Both portable panels from SolarSaga also assure me that I'll have backup power at home in case of emergencies, especially during power interruptions caused by extreme weather or natural disasters.
They may not be able to power my entire house, but at least they'll allow me to charge my mobile phone and other small electronic devices so I can receive news and communicate with the world outside my home — which can honestly spell the difference between life and death during a disaster.
Which Type of Solar Panel Lasts Longest?
Both monocrystalline and polycrystalline silicon solar panels last for a long time, with lifespans that go beyond their 25-year warranties. However, there are pros and cons to both.
First, let’s see how you can tell them apart.
Monocrystalline silicon panels are the most efficient type of panel for harvesting solar energy.  They are dark, with solar cells shaped like squares with cut-off corners.
However, their high efficiency comes doesn’t come cheap, as they are typically more expensive than polycrystalline panels.
Solar panels last about 20 years, according to the Federal Trade Commission. The great news is that, with proper maintenance, your panel may actually run for as long as 40-50 years.
Polycrystalline silicon panels, on the other hand, are blue in color. They look as if they have shiny confetti inside, which are actually silicon crystals.
Between these crystals, there are gaps that “trap” some of the electrons, which make these panels less efficient than their monocrystalline counterparts.
What Makes Your Solar Panels Become Less Efficient?
By now, you should know a thing or two about choosing a panel that will last long. Now let’s see how long do solar panels last when faced with things you can’t control.
High heat can cause cracks that allow moisture to get inside. Now moisture is a big issue because it doesn’t only reduce your panel’s energy output but also increases its degradation rates.
In extreme cases, heat can discolor the panel, which makes your whole solar energy system less efficient.
A strong wind can cause the entire structure to vibrate, loosening the fasteners that hold different parts of your solar system together. These wind vibrations are just as bad for your panels as the vibrations caused by any piece of machinery.
If your solar array isn’t installed correctly, rain can cause corrosion which reduces your system’s efficiency and increases its degradation rates. Corrosion can also weaken its metal understructure and framing.
Freezing temperatures can cause solar panels to warp, cells to crack, and frames to move apart. Now add a thick layer of snow on top of that, and guess how much extra weight do panels and the mount have to suffer.
Yes, solar panels go bad because their energy output reduces over the years of operation. Materials used to convert solar energy into electric energy lose their properties over time, at a rate between 0.3% to 0.8% per year.
Molar solar panels lose their manufacturer’s warranty after 25 years, which means that the owner is solely responsible for their repair and maintenance. Although you can easily find panels with 25-year warranties, most systems last much longer than that, but with reduced power output.
No, solar panels don’t need a lot of maintenance. You should, however, have them periodically checked by your solar provider. Just one inspection can discover problems such as mechanical or electrical faults. Dirt and leaves make your panels less efficient, so you also need to wash them off from time to time.
You can sell old solar panels, give them away, or pay for them to be recycled. If you decide to sell them, don’t expect a good price, as there’s little demand for used solar equipment. Paying for them to be recycled or disposed of as e-waste is the best option from an environmental point of view.
How long does a solar panel last depends on the panel type you choose, the local climate, your maintenance routine, and the brand you go for.
You need to be careful with extreme temperatures, wind, and snow as they can damage your panel’s components. Keep an eye out on dirt and debris on the panel surface as well since they can reduce its efficiency.
But the most effective way to make your solar panels last long is to choose a solar provider that offers a solid warranty.
SunPower’s 25-year warranty covers the complete solar system, even if you decide to install new parts in the future. They also guarantee that the panel power won’t fall for more than 8% after 25 years.
To see how much you can save with their solar system, get a free estimate of your home’s solar energy potential now.
Nikola uses his background in electrical engineering to break down complex sustainability topics for GreenCitizen’s readers. He is a firm believer in environmental conservation, which he practices daily through recycling and home-grown food. He enjoys hiking, engaging in white-water sports, and collecting pocket knives.