Solar Panel Degradation: How Much Power Do Panels Lose Over Time?
By Solar Cost Predictor Team · August 11, 2026 · 6 min read
"Solar panels last 25-30 years" doesn't mean they suddenly stop at that point — it means they continue producing, gradually declining in output, which performance warranties guarantee a minimum level of.
Typical Degradation Rate
Most modern panels degrade at roughly 0.3–0.5% per year. A panel starting at 100% output might still produce around 87–92% of its original output after 25 years — a meaningful but gradual decline, not a cliff.
What Causes Degradation
Normal UV exposure, temperature cycling (expansion and contraction with daily and seasonal temperature swings), and natural material aging in the silicon cells all contribute gradually over decades — it's an expected physical process, not a sign of a defective panel.
How Performance Warranties Protect You
Manufacturers typically guarantee panels will still produce at least 85–92% of original output at year 25 — if your panels degrade faster than that guaranteed curve, the manufacturer replaces or compensates for the shortfall under warranty.
Frequently Asked Questions
Do solar panels stop working after 25 years?
No — they continue producing electricity well past 25 years, just at a somewhat reduced output than when new, typically still 85%+ of original production.
How much power do solar panels lose per year?
Most modern panels degrade at roughly 0.3–0.5% per year, meaning a gradual, predictable decline rather than a sudden drop.
What happens if my panels degrade faster than expected?
Manufacturer performance warranties guarantee a minimum output level (typically 85–92% at year 25) — if your panels fall below that guaranteed curve, you're entitled to repair, replacement, or compensation under warranty.