Solar panels needed for 500 kWh per month
12 panels
of 400 W (4.6 kW) cover 500 kWh/month at 4.5 peak sun hours · about $12,963 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 | 6.9 kW | 18 | 387 sq ft |
| 3.5 h | 6.0 kW | 15 | 322 sq ft |
| 4 h | 5.2 kW | 14 | 301 sq ft |
| 4.5 h | 4.6 kW | 12 | 258 sq ft |
| 5 h | 4.2 kW | 11 | 236 sq ft |
| 5.5 h | 3.8 kW | 10 | 215 sq ft |
| 6 h | 3.5 kW | 9 | 194 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 500 kWh a month?
About 12 panels of 400 W (4.6 kW) with 4.5 peak sun hours; 9 in a 6-hour sunny climate and 15 at 3.5 hours.
What does a 4.6 kW system cost?
At a typical $2.50-$3.20 per watt installed: $11,574-$14,815 before incentives.