Solar Panel Output Estimation Guide
Estimate daily and annual solar generation from panel rating, sun hours, and system losses.
A simple planning estimate is:
Daily energy (kWh) = array wattage (kW) × peak-sun hours × system efficiency.
| Input | Example | Why it matters |
|---|---|---|
| Array rating | 4 kW | Combined nameplate power under test conditions |
| Peak-sun hours | 4.5 h/day | Solar resource expressed as equivalent full-power hours |
| System efficiency | 75–85% | Accounts for inverter, temperature, wiring, dirt, mismatch, and other losses |
| Orientation/shading | Site-specific | Can dominate the result even when panel rating is high |
Example: 4 kW × 4.5 × 0.80 ≈ 14.4 kWh per day, before seasonal variation. Use site-specific irradiance data and professional design for investment decisions.