Solar Panel Warranty explained
Solar panels come with two distinct types of warranty, and understanding both is essential before signing a contract:
1. Product (materials) warranty
Covers manufacturing defects, physical failures, and delamination. Standard product warranties are 10–12 years, with premium manufacturers offering 25 years. A longer product warranty indicates the manufacturer's confidence in build quality.
2. Performance (power output) warranty
Guarantees that the panel will produce at least a specified percentage of its original rated power after a set number of years. Virtually all reputable manufacturers offer:
- 90% output after 10 years
- 80–82% output after 25–30 years
Some premium brands (Panasonic, SunPower) now offer 25-year product warranties AND guarantee 92% output after 25 years, reflecting genuine confidence in their products.
Important caveats: warranties are only as good as the company backing them. Several solar manufacturers have gone bust, leaving customers with worthless warranty papers. Stick to established brands with long trading histories, or ensure your installer will honour the warranty directly.
MCS-certified installers in the UK are required to use MCS-listed equipment, giving you an additional layer of consumer protection.