Solar panels needed for 2,500 kWh per month
58 panels
of 400 W (23.1 kW) cover 2,500 kWh/month at 4.5 peak sun hours · about $64,815 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 | 34.7 kW | 87 | 1,870 sq ft |
| 3.5 h | 29.8 kW | 75 | 1,612 sq ft |
| 4 h | 26.0 kW | 66 | 1,419 sq ft |
| 4.5 h | 23.1 kW | 58 | 1,247 sq ft |
| 5 h | 20.8 kW | 53 | 1,140 sq ft |
| 5.5 h | 18.9 kW | 48 | 1,032 sq ft |
| 6 h | 17.4 kW | 44 | 946 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 2,500 kWh a month?
About 58 panels of 400 W (23.1 kW) with 4.5 peak sun hours; 44 in a 6-hour sunny climate and 75 at 3.5 hours.
What does a 23.1 kW system cost?
At a typical $2.50-$3.20 per watt installed: $57,870-$74,074 before incentives.