Solar Power Rocks logo

Solar Power Rocks - Clear info on home solar power rebates, tax credits, and other benefits

Which company has the best solar panel warranty, and what does it cover?

Avatar for Ben Zientara
Published on 11/30/2017 in
Updated 11/30/2017
hands signing a warranty form

If you’ve spent any time looking at our financial projections for solar in your state, you may have noticed that we look at the energy bill savings you can expect for 25 years after installation. That 25-year timeline wasn’t just plucked out of thin air: it’s the length of time over which most manufacturers guarantee their solar panels will produce electricity.

But that 25-year production warranty is just the beginning. Unlike most big appliance purchases, a solar installation will have up to 3 or 4 various warranties and guarantees each covering something different and working in concert with the others to protect you and your home at the time of installation and for years after.

And although the warranties are written for 25 years, modern solar panels will probably keep working for a decade or two longer than that expiration date. Read on to discover the world of solar warranties!

What kinds of warranties cover solar installations?

A solar installation is made up of solar modules (aka panels), attached to your roof with mounts and racking, wired together with an inverter that converts direct current from the panels to alternating current for your home or the grid.

The manufacturers of solar panels offer two kinds of warranties: a warranty that the panels will be free of defects in materials and workmanship; and a long-term power production warranty. The makers of solar inverters provide warranties for materials and workmanship in their products, too.

Finally, the solar installer will offer a warranty that their work will cause no damage or roof leaks. Solar racks and mounts also come with warranties, but claims are usually handled by the installer. In fact, if you have a warranty claim for any part of your system, you’ll likely go through the installer instead of worrying about contacting the manufacturer.

What does the solar panel materials and workmanship warranty cover?

Solar panels are one of the simplest ways to generate electricity. With no moving parts, all they are is a few layers of photovoltaic and conductive materials encased in extremely durable glass and surrounded by a metal frame.

There’s not much that can break in a solar panel, and each each of the components goes through multiple tests during the assembly process, so once the finished panel rolls off the assembly line it’s ready to go up on a roof and start kicking out kilowatts.

Still, sometimes there’s a stray corner that isn’t properly sealed or a slightly-warped frame, but when these problems occur, they usually happen really soon after installation. So the materials and workmanship warranty covers these things, and most solar manufacturers have materials and workmanship warranties of 10 to 20 years.

Here’s an example from U.S. manufacturer SolarWorld:

Example of solar panel materials warranty

Which solar panel manufacturer offers the best materials and workmanship warranty?

Years of CoverageStart Date
SunPower X- and E-Series25Earlier of date of interconnection or 6 months following delivery
Panasonic25Date of purchase (15 years if not registered with Panasonic within 60 days of purchase)
SolarWorld20Date of sale to original owner
LG Solar12Date of purchase
10Date of sale to original owner
REC Solar
10Date of sale to original owner, not to exceed 10.5 years from date of production
Canadian Solar10Earlier of date of installation or 90 days after delivery
Canadian Solar - Dymond modules10Earlier of date of installation or 90 days after delivery
Yingli Solar10Earlier of date of purchase or 1 year after production
Trina Solar Monocrystalline10Earlier of date of delivery or 12 months after production
Trina Solar Polycrystalline10Earlier of date of delivery or 12 months after production
Sorted best to worst. Current as of 11.30.2017

What does the power production warranty cover?

Here’s where we start getting into the fun! Solar panel production warranties are only in effect as long as the panel is still functioning. In the very rare case that a panel fails for a reason that’s not covered by the materials and workmanship warranty, the power production waranty is null and void.

In the very likely case that the panel is perfectly functional for the lifetime, a power production warranty states that the panel will put out a certain number of watts at a given time. For example, the SolarWorld module warranty states that upon installation, the panel will put out 97% of it’s “effective output,” which is also called “output under Performance Test Conditions” (i.e., real world output under full sun).

Then, SolarWorld says its panels won’t decline by more than 0.7% annually so that “as of the end of the 25th year after purchase, an actual output of at least 80.2% of effective output will be achieved.”

Here’s the SolarWorld production warranty (they call it a “Performance Guarantee”):
Example of solar panel production warranty

Annual vs linear solar production warranties

The two kinds of warranty offered by solar manufacturers dictate the points in time at which the warranty is in effect. An annual production warranty generally states that the panels will still produce a certain % of their rated power by the end of each year after installation. So if the production rate dips below the end-of-year target, the warranty should kick in and the manufacturer should repair the panel.

In the case of a linear rate of decrease, the panels are guaranteed to produce a certain percentage of their rating on day 1, and not to dip below a pro-rated annual rate based on the day of the year. So for example, if the production guarantee decreases by a linear rate of 0.7% per year, that would mean the decrease could not exceed 0.35% by the middle of the year. In the case of an annual warranty, on the other hand the decrease could be as much as 0.7% on January 1st, and as long as it didn’t sip below that, it still wouldn’t trigger the warranty protections.

Here’s how the differences look on a chart:

Comparing solar power production warranties: linear vs annual

Which solar panel manufacturer offers the best production warranty?

CompanyStarting production guarantee% decrease/yrCalculation#of Years
SunPower X- and E-Series98%0.25%annual25
Canadian Solar - Dymond modules97.5%0.5%annual30
LG Solar95% (at the end of 5 years after purchase)0.40%annual25
REC Solar97%0.7%linear25
Trina Solar Monocrystalline97%0.68%annual25
Canadian Solar97.5%0.7%annual25
Yingli Solar97.5%0.7%linear25
Trina Solar Polycrystalline97.5%0.7%annual25
Sorted best to worst. Current as of 11.30.2017

What does the inverter warranty cover?

Inverters also have zero moving parts, unless you count the breaker switches that might be included to disconnect parts of the system from the inverter. But over time, capacitors, computer components and other materials can fail with age and use. Most inverter manufacturers offer materials and workmanship warranties of 10 years that cover any failures of those components before that time.

It’s important to note there are two main varieties of inverter you’ll come across in residential solar installations. The first is called a “grid-tie” inverter, in that it is the piece of equipment that receives DC electricity from the solar panels, and converts it to AC electricity that can be used in your home or sent to the grid. The second is called a microinverter, which is a small box that attaches to the backside of a solar module and does the same job.

Because microinverters are smaller, simpler, and designed to withstand the outside environment, warranties tend to be longer.

What’s not covered by inverter warranties?

Of course this varies by company, but here’s an idea, from SMA’s Sunny Boy inverter warranty (PDF):

  • Transport damage
  • Incorrect installation or commissioning
  • Failure to observe the user manual, maintenance requirements and intervals
  • Modifications, changes or attempted repairs
  • Incorrect use or inappropriate operation
  • Insufficient ventilation of the device
  • Failure to observe the applicable safety regulations
  • Force majeure (e.g. lightning, overvoltage, storm, fire)
  • Cosmetic defects which do not directly influence energy production, or degrade form, fit, function

Which inverter manufacturer offers the best warranty?

CompanyType# of YearsStart Date
SunPowerMicroInverter25Date of purchase
EnphaseMicroInverter25Earlier of date of install or 4 months following delivery
SolarEdgeGrid-Tie12Earlier of date of install or 4 months following delivery
SunPowerGrid-Tie10Date of purchase
SMA (SunnyBoy)Grid-Tie5-10Date of first commisioning
Sorted best to worst. Current as of 11.30.2017

What does the installation warranty cover?

When a solar installer comes to your house, they’re gonna have a few members of their crew crawling all over your roof and screwing giant bolts through your rafters. Luckily, the solar industry has developed all kinds of great tools and equipment that will keep your roof intact, watertight, and looking great throughout the lifespan of your solar installation.

But sometimes things happen, and that’s when you need the peace of mind that comes with a robust warranty. A good installation warranty will cover both “roof penetrations” and damage to your roof by the installation crew. For example, here’s SolarCity’s Roof Warranty:

Roof Warranty
When we penetrate your roof during a System installation we will warrant roof damage we cause due to our roof penetrations. This roof warranty will run the longer of (A) one (1) year following the completion of the System installation; and (B) the length of any existing installation warranty or new home builder performance standard for your roof (the “Roof Warranty Period”).

That last bit is important; you want to make sure your solar installer isn’t voiding any existing roof warranty, or if they are, that they’re willing to supplant it with their own coverage. As you read above, SolarCity/Tesla covers damage to your roof in their warranty. Sunrun also claims to offer a roof warranty as part of their protection package. Vivint solar does not mention a roof warranty anywhere on their site.

How you can trust a solar panel warranty

One of the things people are most worried about when it comes to solar warranties is “what happens if the installer or manufacturer goes out of business?” That’s a valid concern given that the solar industry has exploded in recent years and, in the U.S. especially, has seen a few high-profile bankruptcies of solar companies.

The good news is, if a solar manufacturer wants its panels to be used in large-scale installations, it has to provide investors in those installations with convincing evidence that its warranty will be honored. The way that is done is by purchasing warranty insurance supplied by an underwriter.

One such underwriter is PowerGuard, which provides insurance to manufacturers of some of the world’s most popular solar panels. PowerGuard and others insure the solar warranties for companies like Trina Solar, Yingli, Canadian Solar, and more.

The bottom line for solar warranties

Which manufacturer has the best solar panel warranty? If you couldn’t tell from the tables above, the winner is SunPower, which offers a 25-year materials and workmanship warranty and guarantees that their panels’ output will decrease by no more than 8% total over 25 years. That 8% guarantee is twice as good as their nearest competitor.

When you’re getting solar installed, make sure you understand the warranties offered by your installer. If you choose to own your system, you’ll likely have warranty paperwork from the manufacturers of your panels and inverters as well as a workmanship warranty on the installation. If you choose third-party ownership, your installed will likely be the sole source of the warranties, supplanting the OEM warranties with their own materials warranty and power production guarantee.

Always make sure you get the manufacturer name and model numbers of any equipment during the quote process. To get help from solar experts near you, simply fill out our quote request form, and take the first step of your solar journey!

Last modified: November 30, 2017

7 thoughts on “Which company has the best solar panel warranty, and what does it cover?

  1. Avatar for Meg Patterson Meg Patterson says:

    Our neighborhood was damaged by hail. The solar companies are charging upwards of $5000 to remove/replace the panels. Worse yet, they say they can’t get around to it for a YEAR!! PPA providers are just as bad, making clients pay for the electricity that could have been generated while the system is off line for roof repair. Total rip off.

  2. Avatar for Anonymous Anonymous says:

    Thanks for one marvelous posting! I enjoyed reading it, you are a great Writer. Keep up the wonderful works on. I’ve added you to my blogroll as well.

  3. Avatar for BTelis BTelis says:

    From the market experiences, ALL the purely PV module manufacturers, sooner or later facing serious problems..

  4. Avatar for John John says:

    Why didn’t Solar Edge make it on your inverter warranty list?

    1. Avatar for Ben Zientara Ben Zientara says:

      It got lost in translation, and has been fixed. Thanks!

  5. Avatar for david david says:

    Plus LG going to be around a very long time and yes less on defect but 10 years is plenty of time and they have the same out put warrenty

  6. Avatar for magnusfl magnusfl says:

    I went with LG 320 some solor world could not match and solaredge as I could 320 which matched my pannels output which enphase could not do as there product which clip to much

Have anything to add?

Your email address will not be published.

Subscribe to get solar news

The Federal Solar Tax Credit Has Stepped Down. It Steps Down Again In:

Learn more about the Federal Solar Tax Credit before it goes away.

Solar Power Rocks is a Wave Solar company

Wave Solar Logo