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About That “25-Year” Panel Warranty

by | July 30, 2021

So you’re getting a 25-year solar panel warranty?  Great news!  But, wait, is it really 25 years…?

Maybe not.  A mistake we see all the time is to conflate the panel warranty with the power warranty.  Both of those warranties come from the panel manufacturer, but only one of them really matters—and it’s probably not the one you were told is 25 years.

“Panel warranty” vs. “power warranty”

A panel warranty is what you imagine when you think of a warranty.  It covers your solar panels against defects or premature wear-and-tear.  Panel warranties on residential solar panels typically range from 10 to 25 years.

A power warranty limits degradation of the solar panels.  This is a solar-specific concept and probably wasn’t on your mind when you first asked about the warranty.  Almost every residential power warranty out there is 25 years.  The key number isn’t the length of the power warranty, but rather the degradation rate, which typically ranges from 0.25% per year all the way up to 0.70% per year.

Why a power warranty may not be as helpful as you think

Imagine you have a 12-year panel warranty and a 25-year power warranty.  If the system breaks in year 13 after the 12-year panel warranty has expired, that power warranty won’t help you.  Power warranties only apply if the system is still working! 

Worse, to take advantage of a power warranty, you have to ship the overly-degraded panel to a lab for the power of the panel to be measured.  Who’s paying for shipping and handling on the way to the lab (and back to your house)?  Unless the warranty explicitly says the manufacturer pays, then you’ll have to pay.

Read more about what makes for a good solar warranty.  (Preview: The SunPower panel warranty is 25 years and covers shipping and handling.)

Do your own homework

Seeing is believing.  That’s why we’ve compiled the facts on residential solar panel warranties that we run into most often in Illinois.  To be sure, there’s nothing wrong with a 10 or 12-year solar warranty—but systems that are under warranty for twice as long tend to last twice as long.

Click the icons below to go straight to the actual warranty!


Warranty: 25-Years


Warranty: 10-Years

Trina Premium

Warranty: 10-Years

Canadian Solar

Warranty: 10-Years

Really, do your own homework

We’ve seen a number of solar proposals that are extremely misleading about the panel warranty.  These proposals claim that the panel warranty is 25 years when it’s really 10 or 12 years.  For example, see the screenshots below:

This proposal offers the customer Trina Premium All Black solar panels.

The proposal claims the panel warranty on these solar panels is 25 years.

After looking up the panel warranty, it’s clear the warranty is 10 years, not 25 years.

Click the screenshot above to be taken straight to the warranty document itself.

This discrepancy is easily discovered by looking up the actual warranty documentation on the panels being quoted in the proposal (we’ve linked to this warranty documentation, for five brands of panels, in the links above). 

And, as a reminder, the panel warranty comes from the manufacturer, not the installer.  Below is a screenshot from the contract associated with the proposal described above.  This contract passes through the manufacturer’s warranty; it does not add to it.  And, as we know, the actual panel warranty on these solar panels is 10 years, not 25 years.

Want to talk to someone about a real 25-year panel warranty?  Contact us using the form below!  Certasun exclusively installs SunPower, the best warrantied solar equipment on the market.


This post was written by Jesse Feinberg.
Jesse is one of Certasun's founders.

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