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Independent U.S. Solar Guidance

Section: Buying Guide

Solar Panel Warranties Explained: Product vs. Performance, and What They're Actually Worth

By ClearWatt Editorial Team · Published June 11, 2026

Close-up of a solar panel's rear specification and certification label listing power rating, voltage, and safety compliance marks
Photo: Veikk0.ma / Wikimedia Commons (CC BY 4.0)

Short answer: Solar panels carry two separate warranties — a product warranty covering manufacturing defects (commonly 20-25 years) and a performance warranty guaranteeing a minimum output percentage over time (commonly 25-30 years). Inverters carry their own, shorter warranty, typically 10-12 years. A long warranty on paper is only as good as the manufacturer’s ability to still exist and honor it decades later — which isn’t guaranteed.

Solar sales materials tend to lead with a single warranty number, usually the biggest one on the page. That number is real, but it’s also only part of the picture — panels actually carry at least two distinct warranties that cover different failure modes, plus a separate and shorter warranty on the inverter, which is arguably the more failure-prone component over a system’s life. Here’s what each one actually covers, how the major manufacturers compare on paper, and why the length of a warranty isn’t the same as the strength of it.

Product warranty vs. performance warranty: two different promises

A product warranty (sometimes called an equipment or materials warranty) covers manufacturing and material defects — cracked cells, delamination, corroded frames, faulty junction boxes — for a fixed number of years. If a panel fails outright because of how it was built, the product warranty is what obligates the manufacturer to repair or replace it.

A performance warranty (also called a power output warranty) is a completely separate promise about how much electricity the panel will still generate as it physically ages and degrades, expressed as a guaranteed percentage of its original rated output at specific milestones, usually stated for year 25 or year 30. All crystalline silicon panels lose some output capacity over time regardless of manufacturing quality — this is normal physical degradation, not a defect — and the performance warranty sets a floor for how much of that decline the manufacturer will guarantee against.

The distinction matters because a panel can be entirely free of manufacturing defects and still underperform its performance warranty if it degrades faster than promised, and conversely a panel could have zero degradation issues but fail under the product warranty for an unrelated defect. They’re independent guarantees, and a quote or spec sheet that only cites one number is telling you half the story.

Inverter warranties are shorter, and that gap matters

Standard string inverters typically carry a manufacturer warranty of 10 to 12 years — noticeably shorter than the 20-to-30-year terms common on panels. Since most residential solar systems are designed to run for 25 years or more, a string inverter will often need replacement at least once during the system’s useful life, at a cost the original installation quote may not have flagged clearly. Extended inverter warranties are sometimes available for purchase, and it’s worth asking any installer directly what a replacement costs after the standard warranty period ends, since that’s a real future expense that a panel-focused warranty conversation tends to skip over entirely.

How the major manufacturers compare on paper

Warranty terms vary meaningfully by brand and even by product line within the same brand. Based on manufacturer-published terms:

Notice the spread even among the products listed here: product warranty terms range from 12 to 25 years, and guaranteed output at the end of the performance term ranges from roughly 83% to 92%, depending on brand and product line. Neither number is standardized across the industry, so it’s worth reading a specific product’s warranty document rather than assuming “25 years” means the same coverage across every brand.

Warranty length means little if the company doesn’t survive it

A warranty is only enforceable against a company that still exists — and solar manufacturing has a real track record of companies exiting the business or going bankrupt mid-warranty-term, which changes what a “25-year warranty” is actually worth in practice.

LG announced in February 2022 that it was exiting the solar panel manufacturing business entirely, but the company chose to continue honoring warranties already issued on panels already installed. That outcome was a business decision LG made, not a legal requirement imposed on it — a different company in the same position could have handled it differently.

SunPower Corporation’s case is more complicated and more recent. SunPower filed for bankruptcy in August 2024. Maxeon Solar Technologies, a separate legal entity that had already split from SunPower Corp before the bankruptcy, announced it would continue providing warranty support for SunPower-branded panels despite SunPower Corp’s collapse. Homeowners with SunPower panels installed before the bankruptcy weren’t left with a worthless warranty, but that outcome depended on the specific corporate structure separating Maxeon from the entity that failed — not on any general rule that warranties survive a manufacturer’s bankruptcy.

Both cases point to the same practical lesson: a manufacturer’s financial stability and U.S. market track record are separate questions from the warranty document’s stated length, and worth researching independently before treating “25-year warranty” as a settled promise. A shorter warranty from a financially stable, long-established manufacturer can be worth more in practice than a longer one from a newer or less stable company.

What to actually check before signing

When comparing warranty terms across installer quotes, get both numbers in writing for each product being proposed — the product warranty length and the performance warranty’s guaranteed output percentage at its final year — rather than accepting a single headline figure. Also ask specifically about the inverter warranty length and replacement cost after it expires, since that’s the shorter-dated coverage most likely to become a real out-of-pocket expense during the system’s life. For a broader framework on evaluating an installer’s overall quote, including warranty documentation as one required line item, see How to Compare Solar Quotes, and check the installer’s own track record using the criteria in Red Flags When Choosing a Solar Installer — a company’s stability matters as much for warranty enforcement as the manufacturer’s does.

This article summarizes manufacturer-published warranty terms as of the dates cited; it isn’t a guarantee of any specific product’s current terms, which change over time and should be confirmed directly with the manufacturer or installer before purchase.

Sources

Frequently asked questions

What's the difference between a product warranty and a performance warranty on solar panels?

A product warranty covers manufacturing and material defects — cracked cells, faulty junction boxes, frame corrosion — for a set number of years, commonly 20 to 25 depending on the brand. A performance warranty is a separate guarantee about how much electricity the panel will still produce as it ages, expressed as a percentage of its original rated output at a given year, typically year 25 or year 30. A panel can be free of defects and still fall short of its performance warranty if it degrades faster than promised, so the two numbers need to be checked separately.

How long do solar inverter warranties typically last?

Standard string inverters typically carry a 10 to 12 year manufacturer warranty, noticeably shorter than the 20-to-30-year warranties common on the panels themselves. Since a string inverter often needs replacement at least once during a system's usable life, ask an installer directly what a replacement costs after the warranty period and whether an extended inverter warranty is available for purchase.

What happens to my solar panel warranty if the manufacturer goes out of business?

It depends entirely on the company's legal fate, and there's no government backstop that guarantees a defunct manufacturer's warranty gets honored. LG exited solar panel manufacturing in February 2022 but continued honoring its existing 25-year warranties as a company decision, not a legal requirement. SunPower Corporation's August 2024 bankruptcy is a more complicated case: the legally separate company Maxeon Solar Technologies has said it will provide continued warranty support for SunPower-branded panels, but that arrangement reflects Maxeon's own choice and business structure, not an automatic right a homeowner can enforce against a bankrupt company.

Which solar panel brand has the longest warranty?

Among the manufacturers with publicly documented warranty terms, Silfab Solar's stated terms extend furthest on paper — a 25-year product warranty paired with a 30-year performance warranty guaranteeing at least 82.6% of original output at year 30. Panasonic's EverVolt line matches the 25-year product term with a 25-year performance warranty. Whether the longest stated number matters more than the manufacturer's financial stability and U.S. service history is a separate question worth weighing before choosing on warranty length alone.

Does a longer solar panel warranty always mean a better deal?

Not by itself. A 25-year warranty from a company that doesn't exist in year 15 is worth less than a 20-year warranty from a company still operating and honoring claims. LG's exit from panel manufacturing and SunPower's 2024 bankruptcy are both real examples of warranty terms outliving, or nearly outliving, the company that wrote them. Warranty length is one input; the manufacturer's financial track record and U.S. market presence are separate inputs worth checking independently.

Written by

ClearWatt Editorial Team

The ClearWatt Editorial Team researches and writes every guide on this site. We work from primary sources — federal and state agencies (EIA, NREL, DSIRE, IRS), legislative text, utility rate schedules, and manufacturer documentation — rather than summarizing other websites' coverage of the same topic. We are not licensed solar installers, financial advisors, or tax preparers, and nothing published here is a substitute for advice from one. When a figure can't be traced to a specific, current source, we say so and give a range instead of a false-precision number. Articles are dated, and we correct confirmed errors promptly. See our Editorial Policy for the full standard every guide is held to, and About & Methodology for the sources we draw from.