Solar panels are warrantied for 25-30 years, but they don't maintain 100% of their output throughout that period. Understanding degradation rates helps you set realistic long-term energy expectations and evaluate panel quality.
Light-induced degradation (LID): Occurs in the first few hours of operation. Boron-doped monocrystalline panels (standard) lose 1-3% in the first week. PERC and n-type panels have lower LID.
Long-term degradation: The gradual, ongoing annual output decline over the system's life.
| Panel Technology | Year 1 LID | Annual Degradation | Year 25 Output (550W panel) |
|---|---|---|---|
| Standard monocrystalline (BSF) | 2-3% | 0.5-0.7%/year | ~430-460W |
| PERC monocrystalline | 1-2% | 0.4-0.55%/year | ~455-475W |
| TOPCon (n-type) | <0.5% | 0.3-0.4%/year | ~480-495W |
| HJT (heterojunction) | <0.5% | 0.25-0.35%/year | ~485-500W |
Most tier-1 panel warranties guarantee:
High UV exposure and heat accelerate some degradation mechanisms. Philippine panels degrade approximately 10-15% faster than panels in temperate climates. This is why using the conservative 0.7%/year figure (rather than the 0.5% manufacturer claim) gives more realistic long-term projections.
Compare panel specifications from verified installers at solarenergyph.shop.
Engr. Jason Morales — Founder, SolarEnergyPH