Efficiency comparison by panel type
| Panel Type | Efficiency | Temp. Coefficient | Lifespan | Warranty | Rating |
|---|---|---|---|---|---|
| Monocrystalline (Tier 1) | 20–23% | -0.35%/°C | 25–30 yr | 25 yr | ★★★★★ |
| Bifacial | 22–26% | -0.32%/°C | 25–30 yr | 25 yr | ★★★★★ |
| Polycrystalline | 15–17% | -0.45%/°C | 20–25 yr | 10–15 yr | ★★★☆☆ |
| Thin-film | 10–13% | -0.20%/°C | 15–20 yr | 10 yr | ★★☆☆☆ |
Lower temperature coefficient = better performance in hot Philippine weather. Monocrystalline panels have the best balance of efficiency and heat tolerance.
Key efficiency metrics explained
How much output drops per °C above 25°C. In PH heat (roof temps of 50–70°C), a -0.35%/°C panel loses ~10% output, while a -0.45%/°C panel loses ~14%. Choose lower = better.
Panel output measured at 25°C with 1000W/m² irradiance. This is the lab rating — real-world output in the PH is typically 75–85% of STC due to heat and real sunlight conditions.
Real-world test at 45°C with 800W/m². A 400W STC panel might produce only ~300W at NOCT. This is closer to what Filipino homeowners actually get.
How much efficiency drops each year. Tier 1 panels degrade 0.5–0.7% per year (86% output after 25 years). Low-quality panels can degrade 1%+ per year.