Solar Panel Warranty: Product, Performance, Workmanship

A solar panel warranty is not a single document. It is typically three separate guarantees, each covering a different kind of failure. When a panel underperforms, the first step is to determine which warranty applies, because each has its own duration, coverage, and remedy.

This page explains the three types of warranties, what they cover, and what to check in your specific contract. Warranty terms vary by manufacturer and installer, and are subject to local regulations. Always read the actual warranty documents for your system.

The Three Types of Solar Warranties

Solar warranties fall into three categories:

• Product warranty (also called materials and workmanship warranty): Covers defects in the panel’s manufacturing and materials. This includes things like cracked glass, delamination, or failed junction boxes.
• Performance warranty (also called power output warranty): Guarantees that the panel will produce a certain percentage of its rated power over time. This covers natural degradation, not defects.
• Workmanship warranty: Covers the quality of the installation itself, provided by the installer. This includes issues like roof leaks or loose connections.

Each warranty has a different duration and covers different failures. A panel can be covered by one warranty but not another.

Product Warranty

The product warranty is the most straightforward. It covers defects in the panel’s physical construction. If a panel fails due to a manufacturing defect, the manufacturer will repair or replace it. Typical durations are 10 to 25 years.

What it covers:

• Cracked or broken glass (if not caused by impact)
• Delamination (layers separating)
• Corrosion of the frame
• Failed junction boxes or connectors

What it does not cover:

• Damage from improper installation
• Damage from environmental events (hail, wind, lightning)
• Damage from animals or pests
• Normal wear and tear

Performance Warranty

Performance warranty is about power output. It guarantees that the panel will produce at least a certain percentage of its rated power after a certain number of years. For example, a common performance warranty guarantees 90% of rated power after 10 years and 80% after 25 years.

This warranty covers degradation, which is the natural decline in output over time. All solar panels degrade, typically 0.5% to 1% per year. The performance warranty sets a floor on how much degradation is acceptable.

If a panel’s output falls below the guaranteed level, the manufacturer will provide a remedy, which may be a replacement, a refund, or a prorated credit.

Performance warranty does not cover:

• Shading, soiling, or other external factors
• System design issues (e.g., inverter mismatch)
• Damage from installation errors

Workmanship Warranty

The workmanship warranty is from the installer, not the manufacturer. It covers the quality of the installation. This includes roof penetrations, wiring, and mounting. Typical durations are 1 to 10 years, with 5 years being common.

What it covers:

• Roof leaks caused by installation
• Loose racking or bolts
• Improper wiring that causes system failure
• Inverter installation errors

What it does not cover:

• Defects in the panels themselves (that’s product warranty)
• Natural degradation (that’s performance warranty)
• Damage from third-party modifications

Which Warranty Applies When a Panel Underperforms?

When a panel produces less than expected, the cause determines which warranty applies. The table below summarizes the typical scenarios.

What People Get Wrong About Solar Warranties

A common mistake is assuming that a performance warranty covers any drop in output. In fact, performance warranties only cover degradation that is within the manufacturer’s expected range. If your panel produces 80% of rated power after 5 years, that is likely a defect, not degradation, and would be covered by the product warranty, not the performance warranty.

Another mistake is thinking that the workmanship warranty covers the panels themselves. It does not. The workmanship warranty covers the installation, not the equipment. If a panel fails due to a manufacturing defect, the installer is not responsible.

People also often misunderstand the duration of warranties. A 25-year product warranty does not mean the panel will work perfectly for 25 years. It means the manufacturer will repair or replace it if it fails due to a defect during that time. Normal degradation is expected and covered by the performance warranty.

Finally, many assume that all warranties are transferable. Some are, some are not. If you sell your home, the new owner may not be covered. Check the warranty terms for transferability.

What to Check in Your Warranty

When reviewing a solar warranty, look for the following:

• Duration: How long does each warranty last? Product and performance warranties are often 25 years, but workmanship may be shorter.
• Coverage: What exactly is covered? Read the exclusions carefully.
• Remedy: What will the manufacturer do if a claim is valid? Replacement, repair, or refund?
• Transferability: Can the warranty be transferred to a new owner?
• Claims process: How do you file a claim? What documentation is needed?
• Exclusions: What is not covered? Common exclusions include acts of God, improper installation, and unauthorized modifications.

Local Regulations and Variations

Warranty terms are not set by law. They are contractual agreements between you, the manufacturer, and the installer. However, some states have regulations that affect warranties. For example, some states require that solar panels be covered by a performance warranty for at least 25 years. Others have specific requirements for workmanship warranties.

Because these regulations vary by state and can change, it is essential to check the laws in your jurisdiction. The contract itself is the final authority. If there is a conflict between the warranty and local law, the law may override the contract, but that is not always the case.

Always keep copies of all warranty documents and any correspondence with the manufacturer or installer. In the event of a claim, you will need to provide proof of purchase and installation date.

Filing a Claim

If you believe a warranty claim is valid, follow these steps:

1. Document the issue: Take photos, record the date, and note the system’s performance.
2. Contact the installer or manufacturer: Start with the company that provided the warranty. They will guide you through the claims process.
3. Provide necessary information: This may include the panel serial number, installation date, and proof of purchase.
4. Allow for inspection: The manufacturer may send a technician to inspect the panel.
5. Follow up: Keep records of all communication and follow up if you do not receive a response.

If the claim is denied, you may have recourse through your state’s consumer protection agency or through legal action. However, most claims are resolved without legal intervention.

Conclusion

Solar warranties are three distinct documents covering different aspects of your system. Understanding which warranty applies to a given issue is the first step in resolving it. Always read the actual warranty documents and check local regulations, as they can affect your rights. If in doubt, consult a professional.