Solar Panel Warranty Guide — What to Look For in 2026

Two Types of Solar Panel Warranty

Every reputable solar panel comes with two separate warranties that protect different aspects of your investment:

1. Product Warranty (Workmanship/Materials)

Covers manufacturing defects including cell cracking, delamination, junction box failure, frame corrosion, and glass breakage not caused by external forces. Industry standard: 12–25 years. LONGi Hi-MO 7: 12 years.

2. Performance Warranty (Power Output)

Guarantees the panel will produce a minimum percentage of its rated output over time. This protects against excessive degradation. LONGi Hi-MO 7: 87.4% output at year 30 (1% first-year, 0.4%/year thereafter).

Warranty Comparison by Manufacturer

What Voids a Warranty

• Installation by non-qualified personnel
• Physical damage from improper handling or pressure washing
• Modifications to the panel (drilling, cutting)
• Use in conditions outside rated specifications
• Failure to follow maintenance guidelines

Why Manufacturer Bankability Matters

A 30-year warranty is only as good as the company behind it. LONGi is the world's largest solar manufacturer with strong financials and a global service network. Choosing a bankable Tier 1 manufacturer ensures your warranty will be honoured decades from now.

Frequently Asked Questions

What is the best solar panel warranty in 2026?

LONGi Hi-MO 7 states a 12-year product warranty plus a 30-year performance warranty guaranteeing 87.4% output. This is backed by the world's largest solar manufacturer.

What does "linear performance warranty" mean?

A linear warranty guarantees a steady, predictable decline in output (e.g., 0.4% per year) rather than a step-down at the end. LONGi Hi-MO 7 offers a linear warranty.

Can I claim warranty if my panels underperform?

Yes, if output falls below the warranted level. You will need to provide evidence (monitoring data) and ensure the panels were properly installed and maintained.