Key Takeaways
- Every panel carries two separate promises: a product warranty on build quality and a power warranty on output, and they almost never share the same length.
- Product warranty (typically 10-15 years, up to 25 on premium N-type) covers defects in the panel itself. Power warranty (usually 25-30 years) guarantees a minimum percentage of rated output over time.
- The power warranty is a degradation curve, not a fixed number. Most modules guarantee roughly 84-88 percent of nameplate output at year 25.
- Read the fine print for pro-rated payouts, and check who pays for shipping and labour, because those clauses decide whether a claim is worth filing.
- For a subsidy under PM Surya Ghar, your panels must sit on the MNRE ALMM list, which sets minimum warranty terms.
The first time a client asked me to explain the two big numbers on a datasheet, I realised most people buy panels the way they buy a phone: they look at the wattage and the price and skip everything else. But a solar panel warranty is really two promises stapled together, and confusing them costs people money years later. One covers the physical panel. The other covers how much electricity it still makes in 2046. Get the difference wrong and you either overpay for coverage you do not need, or you assume you are protected when you are not.
The two warranties printed on every spec sheet
Pull up any module datasheet and scroll to the bottom. You will see two warranty figures, and they are rarely the same length. I have watched buyers assume a "25 year warranty" means the whole panel is guaranteed for 25 years. It usually does not.
Product warranty (materials and workmanship)
This is the promise that the physical panel is not defective. It covers manufacturing faults: delamination, a cracked junction box, corroded busbars, a failed bypass diode, frame separation, or backsheet failure. If the panel itself breaks down because of how it was built, the maker repairs or replaces it under this clause.
Product warranties in India typically run 10 to 12 years on budget modules, 15 years on mid-tier, and up to 25 years on premium N-type (TOPCon and HJT) lines from Tier-1 makers. This is the number that actually matters most in the first decade, because that is when workmanship defects show up.
Power warranty (performance or output)
This is the longer number, usually 25 or 30 years. It does not promise the panel stays perfect. It guarantees the panel will still produce at least a stated percentage of its rated output at each year. Solar cells lose a little output every year, a process called degradation, and the power warranty puts a floor under how much loss the maker will accept before compensating you.
How a power warranty actually works
A power warranty is a curve, not a single figure. It has two parts: a first-year drop (higher, because cells settle when first exposed to light) and then a slower annual decline. A typical modern PERC panel might guarantee 98 percent output after year one, then lose no more than about 0.55 percent per year, landing near 84.8 percent at year 25. Premium N-type modules degrade slower, often guaranteeing 87 to 90 percent at year 25 or even year 30.
The panel technology drives that curve. N-type cells hold output better than older P-type PERC, which is one practical reason the warranty on newer modules is stronger. If you are weighing cell types, my breakdown of TOPCon, PERC and HJT degradation rates shows how the numbers differ in the field. I also tracked my own array's degradation over three years, and the measured loss ran below the warranty line, which is what you want to see.
Product vs power warranty at a glance
| Feature | Product warranty | Power warranty |
|---|---|---|
| What it covers | Physical defects, workmanship | Minimum electrical output over time |
| Typical length | 10-15 years (up to 25 on premium) | 25-30 years |
| What triggers a claim | Delamination, cracked frame, dead diode | Output falls below guaranteed curve |
| How you prove it | Visual inspection, panel serial number | IV-curve or flash test, monitoring data |
| Common remedy | Repair or replacement panel | Repair, replacement, or pro-rated cash |
| Who it matters to most | First 10 years of ownership | Later years, resale value |
The fine print that decides whether a claim pays
Two warranties can read identically on the top line and behave completely differently once something goes wrong. These are the clauses I tell every buyer to check before signing.
- Pro-rated vs full replacement. Some power warranties pay only a shrinking fraction as the panel ages. A pro-rated clause at year 18 might cover a fraction of a new panel's value, not the whole thing.
- Shipping and labour. Many warranties replace the panel but make you pay to ship the faulty one back and pay a technician to swap it. On a single panel that can wipe out the value of the claim.
- Transferability. If you sell the house, does the warranty pass to the buyer? A transferable warranty adds real resale value.
- Company survival. A 30-year warranty is only as good as the company behind it. A local Tier-1 brand with an Indian service arm beats a cheaper importer that may not exist in 2040.
Tip: Ask your installer for the actual warranty PDF from the manufacturer, not just the brochure line. The brochure says "25 years". The PDF tells you whether it is pro-rated, whether labour is included, and what documentation you must keep. File that PDF with your commissioning report.
What warranties do not cover
Both warranties have a long list of exclusions, and most rejected claims fail here rather than on the covered fault itself. Damage from improper installation is the big one, which is why using a certified installer protects your warranty, not just your roof. Physical damage from hail, storms, falling branches, or animals is not a manufacturing defect, so that sits with your property insurance, not the panel maker.
Other common exclusions: unauthorised repairs, running panels outside their rated voltage or temperature, cosmetic marks that do not affect output, and problems traced to a mismatched or faulty inverter rather than the panel. Hot spots are a grey area worth understanding, because whether they count depends on the cause. My guide to what causes panel hot spots and how to fix them covers which ones are defects and which are shading or debris issues you caused.
Warranties in the Indian context
If you are claiming a residential subsidy, warranty terms are not just a buying preference, they are a rule. Panels must appear on the MNRE Approved List of Models and Manufacturers (ALMM), and the empanelled vendor installing your system must offer minimum warranty coverage under the scheme. You can read the official terms on the PM Surya Ghar portal and the module standards on the MNRE site.
In practice, most Indian Tier-1 makers (Waaree, Adani, Vikram Solar and similar) offer a 12-year product warranty and a 25-year performance warranty on mainstream P-type lines, with newer N-type ranges pushing product cover to 15 years or more. BIS certification (the Indian equivalent of IEC 61215 and 61730 testing) is a baseline you should confirm on the datasheet.
How to file a warranty claim
I have walked two clients through claims. The panels were replaced both times, but only because the paperwork was in order from day one. Here is the sequence that works.
- Gather your evidence. Photos of the fault, the panel's serial number, your original invoice, the commissioning report, and monitoring data showing the output drop.
- Confirm you are inside the window. Check whether the fault is a product defect or an output shortfall, then match it to the right warranty period.
- Call your installer first. A good EPC handles the manufacturer paperwork for you. This is why the installer you choose matters as much as the panel brand.
- Escalate to the manufacturer. If the installer is gone or unresponsive, contact the brand's Indian service arm directly with your evidence pack.
- Allow a test. For power claims the maker often requires an IV-curve or flash test to prove output has fallen below the guaranteed line.
- Confirm the remedy and costs. Get in writing whether they replace, repair, or pro-rate, and who pays shipping and labour.
Safety warning: Never climb onto the roof or disconnect DC strings yourself to inspect a suspect panel. Solar strings carry lethal DC voltage even in daylight, and opening a live connector can cause an arc flash. Document the fault from the ground, and let a certified technician handle any roof or DC work. Doing it yourself can also void the very warranty you are trying to claim.
What to check before you buy
A strong warranty is a signal of how much the maker trusts its own product, so treat it as part of the price, not a footnote. Before you sign, confirm the product warranty length (not just the power figure), whether the power warranty is linear or stepped, who pays labour and shipping on a claim, and whether the brand has a service presence in India you can actually reach. A longer product warranty on a slightly pricier N-type panel often costs less over 25 years than a cheap module you may be swapping out at year 11. The same logic applies to the rest of the system, which is why it pays to think about extending your whole system's lifespan, not just the panels.
Frequently Asked Questions
Is a 25-year solar panel warranty the same as the panel lasting 25 years?
No. The 25-year figure is usually the power warranty, which guarantees a minimum output, not a defect-free panel. The product warranty covering physical faults is often shorter, commonly 10 to 15 years. Good panels frequently outlive both, but the guarantees are separate promises.
What is the difference between a linear and a stepped power warranty?
A linear warranty guarantees a small, steady output drop each year, giving you a predictable floor at every point. A stepped warranty holds a flat percentage for a block of years, then drops to a lower flat level. Linear terms are generally better and are now standard on quality modules.
Does installing panels myself void the warranty?
It usually does. Most manufacturers require installation by a certified professional and will reject claims traced to improper mounting, wiring, or handling. DIY work can also breach the terms of subsidy schemes. If you want the warranty and the subsidy, use an empanelled installer.
Who pays for shipping and labour on a warranty replacement?
It depends on the specific warranty. Many cover only the replacement panel, leaving you to pay return shipping and the technician's labour to swap it. Always confirm this clause before buying, because on a single-panel claim these costs can exceed the value of the free replacement.
Does the warranty transfer if I sell my home?
Many quality warranties are transferable to the next homeowner, which adds resale value, but some require you to register the transfer within a set window. Check the transferability clause in the manufacturer's warranty PDF and keep all original documents with the property records.
Making the warranty work for you
A solar panel warranty is not one number, it is two promises with different jobs, and knowing which is which changes how you shop and how you protect your system. Keep the manufacturer's warranty PDF, your invoice, and your monitoring data together from day one, so that if you ever need to claim, the paperwork does the arguing for you. For the full picture on choosing, sizing, and living with panels, start with our complete guide to solar panels and match the warranty to the system you actually plan to run.
