Solar panels don’t have any moving parts and they rarely fail. But when they do, it can be a real pain.
Relative to the total cost of your system, one solar panel isn’t that expensive. A budget panel might retail for $200, while a premium one might cost twice as much. But if you have a panel failure on your roof, not only do you have to worry about the cost of replacing the part, but the labor cost of having a technician come to your house, diagnose the problem, climb onto your roof, deinstall the bad panel and install a new one.
The price of the service call will normally be more than the cost of the actual panel. Even if the bad solar panel is covered by a warranty, in most cases you’re footing the bill for the service call, which could be hundreds of dollars.
This is why the length of the warranty is so important when you’re comparing solar panels. In general, a product with a longer warranty will tend to be more reliable. While having the cost of a failed panel covered by the company is a good thing, is big reason you want a reliable panel is to avoid system downtime and the cost and inconvenience of a service call.
Solar panels have two part warranties. There is a power warranty, which guarantees that the power output of the panel won’t fall below a certain threshold after 25 years of operation.
Solar panels degrade and generate less power over time. That’s normal, but too much degradation points to poor quality.
Budget panels will have about an 80% power warranty at the 25 year mark. This means that after sitting on your roof for 25 years, the solar panel is warrantied to generate 80% of the electricity that it did when it was new. A premium panel will degrade less, and you’ll find that their power warranties are about 90% or higher at the 25 year mark.
However, the power warranty applies only if the panel is still operating. That’s where the product warranty comes in. The product warranty for a solar panel guarantees that the product won’t fail within the warranty duration.
A 10 year warranty is the minimum warranty that you’ll find for any panel sold for residential use in the United States.
A 10 year warranty with a budget panel is pretty good, but there are some companies that offer 25 year warranties and also include labor coverage. That is, they’ll cover not only the part, but the labor cost of replacement as well.
These manufacturers all offer 25 year product and 25 year or longer power warranties with their products:
South Korea-based LG is a consumer products behemoth that makes everything from smartphones to washing machines. Their solar panels include the NeON 2, NeON R, and NeON 2 Bifacial (ie. two-sided) series.
LG offers a solid warranty with a low degradation limit. While their warranty does include labor, the coverage is limited: a maximum of $450 in labor costs is offered. While LG does have an installer network like Panasonic and SunPower do, the terms of the warranty do not require that you use an authorized LG installer to submit a claim.
Panasonic is a large Japanese corporation that makes the makes the HIT line of heterojunction solar panels. Until recently, Panasonic was doing some solar panel manufacturing in Buffalo, NY, but the company has recently pulled out.
Panasonic offers a strong warranty that includes labor coverage, but to qualify for the full warranty the equipment must be installed by an authorized Panasonic installer. Otherwise, the product warranty is reduced to only 12 years.
Panasonic warranty info: https://na.panasonic.com/us/support/solar-warranty
Silfab is a Canadian solar panel manufacturer that does manufacturing in Toronto, Ontario and Bellingham, Washington. Their current product lineup is the SIL series of monocrystalline panels.
Unlike the other manufacturers listed here, Silfab does not include labor in its 25 year product warranty. However, Silfab does have the distinction of having the longest power warranty of 30 years. However, with a higher 0.5% degradation limit, the Silfab panels may lose more power output than Panasonic or SunPower panels, even though Silfab has the longer warranty.
Solaria is a small California-based company that does manufacturing in both Fremont, California and South Korea. Their product lineup is the PowerXT series, which includes all-black DC panels and AC panels that incorporate microinverters.
Solaria has a very good warranty that includes labor. However, like the case with LG, there is a cap on the labor coverage: $300 on a first visit by an installer, and $200 if a second visit is required to complete the re-installation of the replacement panel.
SunPower is a US-based company that makes a wide range of solar panel products, including the high end X-Series, the more affordable E-Series, and the A-Series which a solar panel that comes with an integrated microinverter.
When it comes to the labor coverage, SunPower’s warranty and claims process is the most clear-cut: contact a SunPower-authorized installer for a replacement.
SunPower panels also have the best power warranty in terms of degradation, with the panel warrantied to be still reaching 92% of its original power output after 25 years.
SunPower warranty info: https://us.sunpower.com/solar-resources/homeowners/warranties
Of all the manufacturers listed here, SunPower probably has the best warranty. It has the best power warranty with the least degradation, and labor is included for 25 years with a relatively straightforward claims process that utilizes their extensive installer network.
SunPower panels are often the most expensive, but in return you get a high performing solar panel with a great warranty.
Keep in mind that even if a company markets a great warranty, actually getting warranty service is a different matter. It’s always possible to fall down a frustrating rabbit hole of customer service, where you’re bounced from person-to-person when you try to make a claim.
It’s an easier situation with an authorized installer program because you can lean on the installer to do the work on your behalf. Whatever the case, just keep in mind that the reality of getting a warranty claim might be different from the glowing marketing materials that a company advertises.
Even if a solar panel has only a 10 year warranty, this doesn’t mean that the manufacturer expects the panel to fail after 10 years. Solar panels have no moving parts, and even budget panels are expected to have very few failures.
In fact, a study by the National Renewable Energy Laboratory shows that new solar panels have a failure rate of only 5 in 10,000 every year. This means that every year, a solar panel has a 0.05% chance of failing, or a total 1.25% chance of failing over 25 years.
That’s really low, and the study wasn’t limited to premium solar panels like the ones listed in this article. This means that even if you go with a budget panel, a panel failure is unlikely.
Still, if you have a large array or simply want to take less risk, one way to predict which solar panels will be more reliable is to select one that is backed by a strong manufacturer’s warranty.