How Many Solar Panels Do I Need?
Published 2026-02-10 · Updated 2026-07-07 · MySunROI Research Team
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System size depends on annual kWh usage, roof space, and sun exposure. A typical US home needs 16–24 panels (6–9 kW) to offset 80–100% of usage.
Sizing formula
Divide annual kWh by 1,400 (rough US production factor) for system kW needed.
- 900 kWh/month ≈ 7–8 kW system
- Modern panels: 380–430W each
- 7 kW ≈ 16–19 panels
- Use our calculator for your state
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Frequently Asked Questions
Should I oversize?
Size to 80–110% of usage unless export credits are strong.