Are there solar panels with a 40-year warranty?

Yes, solar modules with a 40-year warranty do exist, but they remain the exception in the market. The industry standard is a 25-year product warranty and a 25-year performance warranty. Offering 40 years sets an exceptional standard for quality and confidence. This article explains which manufacturers offer 40-year warranties, what these warranties actually cover, and what to look out for in the fine print.

What exactly does a solar panel warranty mean?

When it comes to solar modules, there are generally two different types of warranties that are often confused:

Product Warranty (Material Warranty): This warranty covers manufacturing defects, material flaws, and premature physical failures. It applies regardless of the module's performance.

Performance guarantee: This warranty specifies the minimum percentage of the module’s original rated power that it must still be able to deliver after a certain period of time. A module with a rated power of 500 watts and a warranty of 88% after 40 years must therefore still be able to deliver at least 440 watts after four decades.

Only a few manufacturers worldwide currently offer both types of warranty together—and for over 40 years.

Which manufacturers offer a 40-year warranty?

Maxeon Solar Technologies (formerly SunPower)

Maxeon is the best-known provider with a 40-year warranty. The warranty applies to selected IBC modules from the Maxeon 6 series. Maxeon is a US company, but produces in Asia. Warranty claims are handled through the respective distributor.

SwissWatt One AG — DAVOS Series

SwissWatt One AG, based in Balgach (Canton of St. Gallen, Switzerland), grants a 40-year product warranty on the entire DAVOS product line and Performance Guarantee — including a guaranteed minimum output of 88.85 Wp after 40 years, assuming a maximum degradation rate of 0.4 Wp per year. The warranty is provided directly by SwissWatt One AG, a Swiss company, with no intermediaries or third-party guarantors. Inventory is held in Switzerland—which means replacement delivery within days rather than weeks in the event of a warranty claim.

The DAVOS modules have been independently tested and certified by the SPF Institute for Solar Technology, OST Eastern Switzerland University of Applied Sciences, and TÜV Rheinland. SwissWatt One AG is the winner of the EUPD Research Top Innovation Award 2025 (Category Modules, Switzerland).

What should one pay attention to in the fine print?

Not every 40-year warranty is equivalent. The following points are crucial:

Who is the guarantor? Is it the manufacturer directly, a distributor, or a third-party insurer? In the event of a manufacturer's insolvency, a third-party warranty can become worthless.

What performance threshold is guaranteed? 80 % after 40 years is significantly weaker than 88.85 % after 40 years—even though both are marketed as a “40-year performance guarantee.”

What is the degradation rate defined as? Some manufacturers guarantee only the final value, not the annual rate. A guaranteed maximum degradation rate of 0.4 % per year is a stronger statement than simply a final value after 40 years.

Is the manufacturer here for the long term? A 40-year warranty is only as good as the financial stability of the company behind it.

Conclusion: 40-year warranty is possible — but rare

The market offers solar modules with a 40-year warranty, but the number of providers is limited. Maxeon and SwissWatt One AG are among the few manufacturers that consistently provide this standard with independent verification. For installers and end customers who want to realize a system with maximum planning security, the 40-year warranty is a crucial purchasing criterion — especially in Switzerland, where systems are designed for a lifespan of 30 to 40 years.

Further information about the DAVOS modules and the warranty of SwissWatt One AG: swo.swiss/quality | swo.swiss/faqs