Solar Panel Warranties Explained: Equipment vs Performance vs Workmanship

The three warranty layers

Equipment warranty covers panel defects (25 years standard). Performance warranty guarantees output — typically 90% at year 10, 80–85% at year 25. Workmanship warranty covers installation (varies wildly: 5–25 years). All three matter; never sign a contract with a thin workmanship warranty.

What actually voids them

Unauthorized DIY modifications, unpermitted installs, and failure to register the warranty void coverage. Transferable warranties (to the next homeowner) add resale value. Ask installers for the exact degradation schedule — a 1%/yr vs 0.5%/yr panel costs you real money over 25 years.

Warranty-backed payback math

The 25-year savings figures on PVFig assume ~0.5%/yr degradation — consistent with premium warranties. A panel that degrades 1%/yr produces ~10% less over its life. When comparing quotes, normalize for degradation and warranty length, not just $/W.

How long should a solar panel warranty be?

Equipment: 25 years. Performance: 25–30 years (90% at year 10, 80–85% at 25). Workmanship: demand at least 10 years, ideally 25.

What is a solar performance warranty?

A guarantee of minimum output over time — typically 90% at year 10 and 80–85% at year 25. It protects against excessive degradation.

Are solar warranties transferable?

Most premium panels offer transferable warranties, which protect resale value. Confirm in writing before signing.