Nothing lasts forever, and solar panels aren’t any different.

Being exposed to the elements 24/7/365, they’ll show signs of wear and tear after several years. These include, but aren’t limited to, cracked glass surface, burn marks, and reduced power output. If not dealt with immediately, the drawbacks of going solar will eventually outweigh the benefits.

These signs can also manifest within a solar panel’s lifespan, so manufacturers provide warranties. The market offers two kinds of them: performance and product. While typically provided together, their terms are different. Knowing what’s and what’s not included is crucial to make the most out of your solar panel system.

The Breakdown

Our solar installation company sources our panels and system components from various manufacturers, so the terms may vary. One of them, Trina Solar, offers a 10- to 15-year limited product warranty and a 25- to 30-year performance warranty, depending on the model. Fortunately, you can give our solar experts a call if you need to file a warranty claim.

In fact, warranties are mainly the reason you want a solar professional working on your solar panels. DIY fixes are a good way to render them void, even if it’s an effective solution. There’s so much to lose that self-repairs aren’t worth it.

Anyway, the key takeaway in this section is that a product warranty expires long before a performance warranty. This may be stating the obvious, but it helps remind you that solar panel warranties don’t come as a single agreement.

The Coverages

Here’s where we really get down to the weeds. If not apparent yet, the terms “product” and “performance” should give you an idea that both warranties cover different aspects of a solar panel system. The limitations and exclusions still vary by manufacturer but share a common theme.

As with most product warranties, a solar panel product warranty can only be used if the defect or fault results from a manufacturing error. While manufacturers try their best to minimise defects in their products, a few inevitably get through for reasons outside of this post’s scope.

That said, among the most common defects that may be covered include:

• Cold soldering: Insufficient heat during soldering can lead to a weak connection between the solar ribbon and the solar cells. This prevents proper electrical flow and increases the risk of heat damage to the panel.

• Micro cracking: Also known as micro fractures, these invisible cracks are caused by the thin silicon cells expanding and contracting under weather conditions. Apt quality or process control can mitigate this.

• Back sheet damage: As the term implies, the back sheet protects a solar panel’s back by preventing moisture and ultraviolet (UV) radiation seepage. Cracks in the back sheet are essentially inviting seepage, which can damage the solar cells.

On the other hand, a performance warranty’s coverage is much simpler. The manufacturer only has to guarantee that a panel’s energy production will retain a certain percentage of its initial output over much of its lifetime. This is expressed in two values: the annual degradation percentage and the actual power output by the warranty’s end.

For example, below are the values for Trina Solar’s 25-year power output warranty. Note that these figures only apply to panels with back sheet glass.

*As defined by Section 1 of Trina Solar’s Global Limited Warranty

The sizeable rate of decline in the first year is inevitable due to light and potential-induced degradation. However, the decline stabilises throughout the panel’s service life. Even long after the warranty ends, solar panels can still produce roughly 80% of their initial capacity.

Thanks to technology, property owners can keep track of each panel’s output using advanced monitoring apps that come with the PV system. A panel that’s consistently producing less electricity warrants calling an expert service. Not to mention that only professionals have the skills and tools needed to inspect every nook and cranny of the panel.

Which Matters More?

Product workmanship and performance are both essential in solar panels, let alone solar power systems.

A solar panel’s performance rests on quality components and manufacturing. Poor quality parts and practices risk the solar panel not performing as it’s supposed to or even breaking down. Without a good product warranty as a safeguard, the PV system may as well be a high-risk investment.

However, don’t discount the need for an equally good performance warranty. Consumer NZ suggests getting a PV system that guarantees minimum power production for at least 20 years. It also recommends including technical issues in the coverage. (3)

Conclusion

We advise not to be too focused on just a particular type of warranty. The ideal PV system includes a performance and product warranty with adequate coverage.

References:

1. Bhor A. How Long Does a Solar Power System Last: Solar Panels, Inverter, the Lot? [Internet]. Mysolarquotes.co.nz. My Solar Quotes; 2022 [cited 2025 Jul 9]. Available from: https://www.mysolarquotes.co.nz/blog/solar-technology/how-long-does-a-solar-power-system-last-solar-panels-inverter-the-lot-/

2. Rooftop solar — benefits and tips for your home [Internet]. Gen Less. EECA; 2024. Available from: https://www.genless.govt.nz/for-everyone/at-home/explore-solar-energy/rooftop-solar/

3. Page J le. Are solar panels right for your home? [Internet]. Consumer NZ. Available from: https://www.consumer.org.nz/articles/are-solar-panels-right-for-your-home