You've just invested anywhere between ₹1 lakh and ₹5 lakh in a rooftop solar system. The installer hands over a set of papers and mentions "25-year warranty" somewhere in the conversation. Most homeowners nod, file the documents, and forget about them until something goes wrong.
That's when the real confusion begins. Which warranty applies? What's actually covered? Why did the claim get rejected?
Solar panel warranties are more layered than most people realize, and misunderstanding them can cost you significantly over a 25-year system life.
Every solar panel ships with two completely separate warranties. They cover different problems, run for different durations, and are backed by different parties. Confusing them is how homeowners end up with rejected claims.
1. Product Warranty (Materials & Workmanship)
Think of this as the "it shouldn't break" warranty. The product warranty protects you against defects caused by manufacturing errors, faulty materials, delamination, frame corrosion, junction box failures, and glass breakage under normal operating conditions.
Standard terms in 2026:
Mono PERC panels: 10–12 year product warranty
TOPCon N-type panels: 12–15 year product warranty
Inverters: 5–10 years depending on brand and model
What this means practically: if your panel develops hot spots, cell cracking, or backsheet bubbling within the warranty period and these stem from a manufacturing fault - the manufacturer must repair or replace it at no cost to you.
What this does not cover: damage from improper installation, extreme weather events, lightning strikes, unauthorized modifications, or physical mishandling during cleaning.
2. Performance Warranty (Power Output Guarantee)
This is the longer, more frequently misunderstood warranty. The performance warranty guarantees that your panels will not degrade below a stated minimum output over the warranty period - typically 25 or 30 years.
Industry benchmarks currently applicable in India:
Standard PERC panels: Minimum 80–84.95% of rated output after 25 years
TOPCon N-type panels: Minimum 87.4–88.9% of rated output after 25 years, with 30-year coverage becoming increasingly common
Year-one degradation (LID — Light Induced Degradation): PERC panels lose roughly 1.5–2%; TOPCon panels lose approximately 1–1.2% in the first year
This number matters more than most people think. If your 440W panel drops to 350W by year 15 when the warranty guarantees a minimum of 373W, you have a legitimate claim. The challenge which we'll address below is actually proving and documenting it.
Beyond the manufacturer's two warranties, your installer should provide their own separate workmanship warranty typically 3 to 5 years minimum from a credible installation company. This covers problems that arise from the installation itself: roof leaks caused by incorrect mounting, loose DC wiring, improper earthing, and structural failures due to substandard bracket installation.
This warranty is entirely separate from the panel manufacturer's coverage and from the inverter warranty. A professional installer documents all three ,in writing before you make your final payment.
If an installer cannot produce clear written workmanship warranty terms, treat that as a serious warning sign.
This is where many homeowners discover too late why a legitimate seeming claim was rejected. Manufacturers are specific about the conditions that nullify coverage:
Improper or irregular maintenance: Skipping routine panel cleaning, allowing significant soiling, or ignoring visible damage can be cited by manufacturers as a contributing factor in claim disputes. Keep a maintenance log.
Unauthorized repairs or modifications: Having an uncertified technician open the junction box, tamper with wiring, or perform repairs not sanctioned by the manufacturer voids the product warranty. Always use MNRE-empanelled technicians or the original installer's service team for any work on the system.
Stepping or walking on the panels: This causes micro cracks hairline fractures within the cell that are invisible on the surface but degrade output over time. Micro-cracks are among the most common reasons warranty claims are disputed because they are difficult to attribute definitively to manufacturing versus handling.
Improper cleaning methods: Using abrasive sponges, hard bristle brushes, or high pressure water jets can permanently scratch anti-reflective glass coatings, reducing efficiency and voiding coverage. Manufacturers specify approved cleaning procedures.
Unapproved mounting or structural modifications: Drilling into the panel frame, using non-standard clamps, or installing at angles outside the manufacturer's specified range can all invalidate the warranty.
Natural disaster and accidental damage: Cyclones, flooding, direct lightning strikes, hailstones, and falling objects are standard exclusions from product warranties. Dedicated solar insurance or a broader home insurance policy with solar cover is the appropriate protection for these events.
Gradual underperformance is nearly impossible to spot without data. Most homeowners only notice a problem when there is a dramatic, visible fault — by which point the underperformance may have been occurring for months or years.
The reliable method: Monitor your system's daily kWh output through your inverter's app or monitoring portal and compare it to the same period in previous years. Modern inverters from brands like Huawei, SMA, and Fronius all provide this data. A consistent annual decline of more than 1–1.5% — especially in the early years — warrants a professional inspection.
Signs that justify investigation:
- One string of panels consistently underperforms compared to others on the same roof
- Output drops sharply even after thorough cleaning
- Visible discoloration, bubbling on the rear surface, or hotspots (detectable only with thermal imaging)
- Frequent inverter fault codes or unexpected shutdowns during peak sunlight hours
If you suspect genuine underperformance, contact your installer first. For a formal performance warranty claim, the manufacturer will typically require an I-V curve test — a specialized measurement of actual output versus rated output under controlled conditions, conducted by a certified technician.
Take advantage of government subsidies and reduce your electricity bills with rooftop solar.
Get Free ConsultationSolar panels generally transfer to the new property owner when a home is sold. Both product and performance warranties are typically transferable, but the process requires active steps — it does not happen automatically.
You will usually need to:
- Notify the manufacturer and your original installer in writing within 30–90 days of the property transfer
- Complete a warranty transfer registration form with the manufacturer
- Provide the new owner with original purchase invoices, installation completion certificate, and all service records
Keeping a dedicated folder with your warranty documents, installation certificate, panel serial numbers, and maintenance logs not only protects your claim rights — it also increases the resale value of the property.
Step 1: Contact your installer. Most manufacturers require the installer to initiate and coordinate the claim on your behalf. Do not approach the manufacturer directly as a first step.
Step 2: Gather your documentation — original purchase invoice, installation certificate, serial numbers of the affected panels, clear photographs of the problem, and monitoring data showing the underperformance or fault.
Step 3: Your installer arranges an inspection. For performance claims, this typically involves an I-V curve test by a certified technician. For product defect claims, a visual and electrical inspection is usually sufficient.
Step 4: If the claim is valid, the manufacturer will arrange repair or replacement. Timelines vary — typically 7–21 working days for inspection, and a further 14–30 days for resolution depending on part availability.
Step 5: If a claim is disputed, request a written explanation of the rejection reason. Independent solar inspection services can provide a third-party fault report that can be used to escalate.
A warranty is only as strong as the company and the documentation behind it. Before finalizing your solar installation, confirm three things in writing: the exact product warranty duration and coverage scope, the performance warranty minimum output threshold at year 25, and the installer's own workmanship warranty terms.
Any installer who cannot provide all three — in writing, before payment -is leaving you exposed for a 25-year investment.
Here, every installation comes with complete warranty documentation handed over at commissioning: manufacturer product warranty, performance warranty, inverter warranty, and our own workmanship guarantee. Our service teams are available for the full lifecycle of your system — not just for the first year.
For a free consultation on a new solar installation or to get clarity on an existing system's warranty coverage, reach out to our team today.
Frequently Asked Questions
1. How long does a solar panel warranty last in India?
Product warranty: 10–15 years depending on technology (PERC or TOPCon). Performance warranty: 25–30 years. Inverter warranty: 5–10 years. Workmanship warranty from the installer: typically 3–5 years. All four should be documented separately.
2. Does the performance warranty guarantee my exact electricity bill savings?
No. The performance warranty guarantees a minimum power output level from the panel itself — not your system's overall energy production, which is also affected by inverter efficiency, shading, orientation, soiling, and local weather. It is a panel-level guarantee only.
3. What happens if the manufacturer goes out of business?
This is a real risk with newer or smaller brands. Stick to manufacturers with a documented service presence in India, MNRE empanelment, and an established track record. A warranty from a company that no longer exists is unenforceable. Brand reputation and financial stability are part of your warranty evaluation.
4. Can I extend my solar panel warranty?
Product and performance warranties are fixed at the time of purchase. Inverter warranties can sometimes be extended through paid service contracts. Some installers offer extended maintenance and monitoring plans that effectively extend post-warranty service coverage — these are worth evaluating at the time of installation.
5. What is the difference between a linear and step performance warranty?
A linear performance warranty guarantees a smooth, steady degradation curve year by year. A step warranty only guarantees output at specific milestone years (e.g., year 10 and year 25) with no guarantee for the years in between. Linear warranties offer stronger protection and are the standard for reputable manufacturers.
