Calculate how many solar panels you need for your home. Based on monthly energy usage, location, and panel specifications.
8.4 kW system
| Panels Required | 21 panels |
| System Size | 8.4 kW |
| Peak Sun Hours | 4.5 hrs/day |
| Annual Production Est. | 11038 kWh |
| Est. Roof Space Needed | 368 sq ft |
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Panels = (Daily kWh) ÷ (Panel kW × Sun Hours × Efficiency)
Daily kWh = Monthly kWh ÷ 30
The average US home (886 kWh/month) typically needs 20–25 panels at 400W each, depending on location and sun hours.
Monthly energy consumption, panel wattage, peak sun hours in your area, and system efficiency all affect panel count.
Peak sun hours are the equivalent hours of full sunlight (1000 W/m²) per day. Desert Southwest: 5–7 hrs. Pacific Northwest: 3–4 hrs.
Residential solar panels are typically 400W and about 17.5 sq ft (1.65 m²) in size.
Calculations are for educational purposes only. Consult a qualified financial advisor for personalized advice.