Solar panels needed for 3,000 kWh per month
70 panels
of 400 W (27.8 kW) cover 3,000 kWh/month at 4.5 peak sun hours · about $77,778 before the 30% credit at $2.80/W
System size by peak sun hours
| Peak sun hours | System size | 400 W panels | Roof area |
|---|---|---|---|
| 3 h | 41.7 kW | 105 | 2,258 sq ft |
| 3.5 h | 35.7 kW | 90 | 1,935 sq ft |
| 4 h | 31.2 kW | 79 | 1,698 sq ft |
| 4.5 h | 27.8 kW | 70 | 1,505 sq ft |
| 5 h | 25.0 kW | 63 | 1,354 sq ft |
| 5.5 h | 22.7 kW | 57 | 1,226 sq ft |
| 6 h | 20.8 kW | 53 | 1,140 sq ft |
kW = monthly kWh ÷ 30 ÷ sun hours ÷ 0.8 (inverter, wiring, soiling and temperature losses). Southwest US ~5.5-6.5 h, Midwest/Northeast ~3.5-4.5 h.
FAQ
How many solar panels for 3,000 kWh a month?
About 70 panels of 400 W (27.8 kW) with 4.5 peak sun hours; 53 in a 6-hour sunny climate and 90 at 3.5 hours.
What does a 27.8 kW system cost?
At a typical $2.50-$3.20 per watt installed: $69,444-$88,889 before incentives.