Solar Panel Calculator (How Many Panels?)
Solar panel calculator: how many panels and what system size (kW) cover your electricity use, with yearly production and savings.
kW = daily kWhsun hours × 0.8
How to use this calculator
- Type your input in the box.
- The result updates as you type.
- Use “Copy result” or “Copy link” to share it.
System kW = daily kWh ÷ (peak sun hours × 0.8). The 0.8 accounts for inverter, wiring, heat and dirt losses. US peak sun hours range from about 3.5 to 6.
Frequently asked questions
900 kWh a month with 4.5 sun hours and 430 W panels?
20 panels, an 8.6 kW system.
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