Quick Answer: A warranty for solar panels usually bundles two separate promises: a manufacturer's product warranty against defects and a performance warranty against output degradation, plus a separate workmanship warranty from your installer covering wiring, mounting, and installation errors. Always get both terms in writing.
Industrial and commercial buyers comparing EPC quotes often treat "warranty" as a single number on a brochure. It is not. Before signing a contract, you need to separate what the panel manufacturer promises from what your installer is on the hook for, because these two warranties cover different failures and require different claim paths.
What Is a Solar Panel Warranty and Why It Matters for Your EPC Decision
A warranty for solar panels is a set of promises covering different failure modes over the life of your installation, not a single blanket guarantee. For a plant head or facility manager signing an EPC contract, this distinction affects who you call when something goes wrong and how fast it gets fixed.
Three warranty categories are worth checking in an EPC contract: the product warranty against manufacturing defects, the performance warranty against excessive output degradation, and the installation or workmanship warranty covering the EPC's work. These may be documented separately or included within broader contractual warranty provisions.
What Does a Solar Panel Warranty Actually Cover?
A solar panel warranty typically covers two distinct things: manufacturing defects and output degradation, and buyers should ask vendors to separate both figures in writing.
Product (manufacturing defect) warranty. This covers faults in materials or workmanship at the factory level, things like cell cracking, lamination failure, or junction box defects that show up without external damage. If a panel fails this way within the covered period, the manufacturer typically repairs or replaces it.
Performance (power output/degradation) warranty. Solar panels lose a small percentage of output capacity every year as part of normal aging. A performance warranty, sometimes called a solar panels warranty for output, guarantees the panel will not drop below a specified output threshold during a defined period. This is separate from the product warranty and is usually expressed as a linear degradation curve.
What's typically excluded. Warranties generally exclude damage from improper installation, extreme weather events beyond rated tolerances, unauthorized repairs, and normal wear from environmental exposure like dust or salt corrosion in coastal areas.
Red Flag: If an EPC vendor quotes only one combined "warranty" figure without separating product and performance terms, ask them to put both numbers in writing before you sign anything.
Module Warranty Terms Explained
A solar module warranty is really two overlapping warranties stacked on the same physical product: the product warranty and the linear performance warranty. The product warranty protects against defects in the module itself, the physical panel assembly. The linear performance warranty protects against the gradual, predictable decline in power output that every panel experiences over decades of sun exposure.
Because these two terms are often printed together on a single datasheet, it is easy to assume they mean the same thing. They do not. A panel can be free of manufacturing defects and still fall short of its guaranteed performance curve, or vice versa.
Buyers evaluating EPC vendors should request both terms in writing, not just verbally quoted, before signing a contract. A written quote should state the product warranty duration, the performance warranty duration, and the specific degradation threshold guaranteed at each milestone year.
Installation Warranty vs Panel Warranty: Know the Difference
A solar installation warranty is separate from the panel manufacturer's warranty and covers the quality of the EPC's own work, not the equipment itself.
What your EPC/installer is responsible for. The installer warranty, sometimes called a solar installer warranty, covers workmanship: mounting structure integrity, wiring connections, inverter configuration, earthing, and the overall system assembly. If a leak develops around a rooftop mounting bracket or a wiring fault causes underperformance, this falls under the installer's responsibility, not the panel manufacturer's.
What the panel manufacturer is responsible for. The manufacturer only stands behind the physical panel and its guaranteed output curve, as described in the product and performance warranties above. They are not responsible for how the panel was mounted, wired, or configured on site.
Why this distinction matters when something fails. If your system underperforms, the first diagnostic question is whether the fault lies in a defective panel or in how the system was installed. Routing a claim to the wrong party wastes time, so knowing which warranty applies before a failure occurs saves weeks of back-and-forth.
Buying Tip: Ask your EPC to specify the installation warranty duration separately in the contract, not just reference it as "covered," so there is no ambiguity about what workmanship period you are protected under.
How to Claim Your Solar Panel Warranty
Claiming a solar panel warranty starts with documentation, not a phone call. Follow these steps in order:
Document the issue. Take photos of visible defects and record performance readings (generation data, inverter logs) showing the output shortfall or physical fault.
Contact the installer or EPC first. In most cases, you raise the claim with the company that sold and installed your system, not the manufacturer directly, since your contract is with them.
Reference your invoice and warranty certificate. Both documents establish the installation date, panel serial numbers, and the warranty terms that applied at purchase.
Clarify which warranty path applies. A defective panel claim routes to the manufacturer through your installer; a workmanship issue, like a wiring fault, is the installer's direct responsibility.
Keep a written record of every communication, including dates and names, in case the claim needs escalation.
The warranty claim process depends on the manufacturer's terms and your EPC agreement. Some manufacturers require claims to be submitted through the installer or an authorized service partner, while others allow the system owner to approach them directly.
For installation-related problems, contact the EPC contractor responsible for the work. Before commissioning, confirm who handles manufacturer claims, what documentation is required, and whether the EPC will coordinate repairs or replacements on your behalf.
Warranty Checklist Before You Sign an EPC Contract
Before signing any EPC contract, verify each warranty category separately rather than accepting a single combined figure.
| Warranty Type | What It Covers | Who You Contact | What to Verify in Writing |
|---|---|---|---|
| Product (manufacturing) | Defects in panel materials or assembly | Manufacturer, via installer | Defect coverage duration and replacement terms |
| Performance (degradation) | Power output decline over time | Manufacturer, via installer | Guaranteed output threshold at key milestone years |
| Installation (workmanship) | Mounting, wiring, earthing, inverter setup | Your EPC/installer directly | Workmanship warranty duration and scope of coverage |
Once your warranty terms are confirmed and the contract is signed, the next practical step for industrial and commercial installations is securing your net metering connection. Our step-by-step net metering application guide walks through the discom approval process, required documents, and inspection stages that follow installation.
Frequently Asked Questions
1. Does a Solar Panel Warranty Cover Labor and Replacement Costs?
Not necessarily. A manufacturer's warranty may cover repairing or replacing a defective module without covering the labor, transportation, removal, or reinstallation costs. These expenses may fall under the EPC contractor's obligations or remain the system owner's responsibility, depending on the contract. Check whether these costs are included before finalizing your EPC agreement.
2. Can Solar Panel Warranties Become Invalid?
Yes. A warranty can become invalid if the owner fails to meet the manufacturer's specified conditions. Examples may include unauthorized modifications, improper handling, repairs by unapproved technicians, or installation that does not follow the manufacturer's instructions. The exact conditions vary, so review the exclusions and maintenance requirements in the warranty document.
3. What Happens to a Solar Panel Warranty if the Manufacturer Goes Out of Business?
If a manufacturer shuts down or becomes insolvent, claiming warranty support can become difficult. Whether another company assumes its warranty obligations depends on business arrangements, legal proceedings, and applicable agreements. Buyers should consider the manufacturer's financial stability, service network, and presence in India when evaluating module suppliers.
4. Can Solar Panel Warranties Be Transferred to a New Property Owner?
Some manufacturers allow warranty transfers when a solar installation changes ownership, while others impose notification, documentation, or other conditions. If you sell a commercial property with an existing solar installation, check whether the module warranties and EPC workmanship obligations can be transferred to the new owner.
5. Does Replacing a Solar Panel Reset Its Warranty Period?
Not automatically. Replacement modules may receive coverage for the remaining period of the original warranty or a separate period specified by the manufacturer. The replacement terms should be confirmed in writing so that you know how long the new module remains covered.
6. Do Solar Panel Warranties Cover Damage During Transportation?
Coverage depends on when the damage occurs and who is contractually responsible for the equipment. Damage during transportation may fall under the supplier's or logistics provider's responsibility rather than the manufacturer's product warranty. EPC buyers should clarify who bears the risk of transit damage and who arranges replacements before the equipment reaches the project site.