Solar panels do not stop working on their 25th birthday. While they produce slightly less power each year, a well-built solar array typically continues to perform well long after its 25-year warranty ends.
The lifespan you see on a solar quote is the length of your warranty term, not an expiration date for your panels.
When reviewing your solar quote, remember to focus on three important details:
- How quickly the panels’ power output is expected to decline
- What each of the three warranties covers if something fails
- How the equipment is designed to perform through decades of New Hampshire weather
Solar Panels Fade, Not Expire
Solar panels lose a small amount of output each year, which is known as degradation.
In 2011, the National Renewable Energy Laboratory reviewed roughly 11,000 degradation measurements from about 200 studies and found a median degradation rate of 0.5% to 0.6% per year for crystalline silicon panels. That data spans decades of installed equipment, including much older panel technology.
Today’s panels generally perform better. The two panels we install, from JA Solar and Hyundai, warrant no more than a 1% loss in the first year and 0.4% per year after that. The Hyundai module guarantees 87.4% of its original output at year 30. Older sources citing a 2% to 3% first-year loss are describing an earlier generation of panels.
For example, if a 10 kW array installed in 2026 produces about 12,000 kWh in its first year, it would still produce around 10,500 kWh in year 25. The change is gradual and barely noticeable from year to year, and it is already accounted for in an accurate solar savings estimate.
The Three Types of Warranties
A quote that says “25-year warranty” tells you very little, because a solar installation has three separate warranties. Plus, each one comes from a different company.
Product Warranty
The product warranty covers the panel itself if it fails due to issues such as a manufacturing defect, delamination, or a junction box problem. The panels we install come with a 25-year product warranty. (Link to Them?)
Performance Warranty
The performance warranty guarantees a minimum percentage of the panel’s original power output at a specified year. While 25 years is the standard warranty term, is the standard term, and 80% at year 25 is the industry floor. Our panels carry a 30-year linear power warranty. This means the solar panel’s power output must decrease by only 0.5% each year, smoothly. By year-30, the panels should have 87% power efficiency.
Workmanship Warranty
The workmanship warranty is from the installer, not the manufacturer. It covers the work itself: mounting, flashing, wiring, and the holes made in your roof. Granite State Solar offers a 12-year workmanship guarantee.
Most manufacturers will send a replacement panel if one fails under the product warranty. Most will not pay the labor to remove the failed panel and install the new one. That labor is a service call, which the installer’s workmanship warranty would cover.
Each warranty is only worth as much as the company behind it. A twenty-five-year promise from a company that will not exist in year eight is not valuable. Discuss this with anyone quoting you. Our guide to picking the best solar panels covers what else to compare.
Snow, Ice, and 25 New Hampshire Winters
Solar panels installed in New Hampshire need to withstand significant snow and wind loads. The panels we install are rated for up to 5,400 pascals (Pa) of front-side mechanical load, equivalent to approximately 112 pounds per square foot, along with 2,400 Pa of wind uplift on the back.
Snow loads vary significantly across New Hampshire. Ground snow loads are generally around 50 pounds per square foot along the seacoast and can reach approximately 70 pounds per square foot around Concord and Manchester, with even higher loads in the White Mountains.
Roof Considerations
Strong panels, however, cannot compensate for a roof that isn’t structurally sound. If the roof is too weak, solar PLUS snow could damage it. A thorough site visit includes an assessment of the roof’s age and condition. In some cases, a roof replacement might be recommended before installing rooftop solar panels.
Mechanical Loads to Consider
Hail
Our panels are tested to withstand the impact of hail by firing a 25-millimeter ice ball, about an inch across, at roughly 51 miles per hour at eleven points on the module. Most US hail is at or below that size, and glass breakage generally starts around 45 millimeters.
Cold.
Solar panels are more efficient in cold weather, not less. Winter production Solar production drops here in New Hampshire during the winter primarily because the days are shorter and the sun is at a lower angle.
Snow
When snow accumulates on solar panels, resist the urge to climb onto the roof and clear it. On a pitched array, snow will often slide off as the panel surface warms. Not only can attempting to remove snow from your roof cause injury to yourself, but also it can also damage your panels, which is not covered in any warranties. More on how to get snow off your solar panels.
Freeze-thaw cycling
Repeated freezing and thawing can put stress on roofing materials, flashing, seals, and other components. In many cases, the greater concern isn’t the solar panel itself but the roof and installation details surrounding it. That’s why proper waterproofing, flashing, attachment methods, and overall installation quality matter so much in a climate with frequent temperature swings.
Inverters and Batteries’ Lifespans
The panels are the longest-lived component. Everything else has its own clock.
- Microinverters sit under each panel with their own warranty terms. They give you panel-level monitoring, so an underperforming panel gets flagged instead of quietly costing you production for years. An optimal solar system requires a well-working microinverter.
- Batteries are shorter-lived than solar panels. The Enphase IQ Battery 10C carries a 15-year limited warranty, and the FranklinWH carries a 12-year warranty. See the equipment we install and its terms.
Plan on one inverter or battery replacement across the working life of the panels. That is normal and budgetable, not a system failure. Anyone promising zero attention for thirty years is overselling.
After Install, What You Actually Have to Do
We don’t require an annual service plan or charge a recurring fee for a residential system we install. The Enphase monitoring app helps our customers and our team see how your panels are producing and flag problems remotely. Our service team can see production panel by panel and flag problems remotely, often before a homeowner notices.
We suggest watching tree growth on your property, since shading can creep up over years. If you notice your production is low for an extended period of time, give us a call.
Ask About the Warranty Stack
If you’re comparing solar quotes, ask each company to provide the Product warranty, Performance warranty, and Workmanship warranty in writing and clearly separated.
Understanding what is covered, who is responsible, and what happens when something goes wrong can tell you a lot about the company you’re considering.
Book a free site visit, and we’ll walk you through each warranty and evaluate how your roof and solar system are likely to perform over the next 25 years.
