Solar panels needed for 600 kWh per month
14 panels
of 400 W (5.6 kW) cover 600 kWh/month at 4.5 peak sun hours · about $15,556 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 | 8.3 kW | 21 | 452 sq ft |
| 3.5 h | 7.1 kW | 18 | 387 sq ft |
| 4 h | 6.2 kW | 16 | 344 sq ft |
| 4.5 h | 5.6 kW | 14 | 301 sq ft |
| 5 h | 5.0 kW | 13 | 280 sq ft |
| 5.5 h | 4.5 kW | 12 | 258 sq ft |
| 6 h | 4.2 kW | 11 | 236 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 600 kWh a month?
About 14 panels of 400 W (5.6 kW) with 4.5 peak sun hours; 11 in a 6-hour sunny climate and 18 at 3.5 hours.
What does a 5.6 kW system cost?
At a typical $2.50-$3.20 per watt installed: $13,889-$17,778 before incentives.