PerformanceUp to date · Jan 15, 2026
Annual Degradation
The gradual decline in solar panel output over time, typically 0.3-0.5% per year for modern panels. After 25 years, panels still produce 87-92% of their original rated power.
Why It Matters
Panel warranties guarantee minimum production (usually 80-85% at year 25). Degradation is factored into ROI calculations and is why system sizes are designed slightly larger than needed.
Related Tools
Related Terms
Degradation Rate
The annual decrease in solar panel efficiency. Modern panels typically degrade 0.3-0.5% per year.
Production Guarantee
A written guarantee from a solar installer specifying the minimum kWh of electricity the system will produce annually. If actual production falls short, the installer compensates the difference.