Solar panels needed for 1,400 kWh per month
33 panels
of 400 W (13.0 kW) cover 1,400 kWh/month at 4.5 peak sun hours · about $36,296 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 | 19.4 kW | 49 | 1,054 sq ft |
| 3.5 h | 16.7 kW | 42 | 903 sq ft |
| 4 h | 14.6 kW | 37 | 796 sq ft |
| 4.5 h | 13.0 kW | 33 | 710 sq ft |
| 5 h | 11.7 kW | 30 | 645 sq ft |
| 5.5 h | 10.6 kW | 27 | 580 sq ft |
| 6 h | 9.7 kW | 25 | 538 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 1,400 kWh a month?
About 33 panels of 400 W (13.0 kW) with 4.5 peak sun hours; 25 in a 6-hour sunny climate and 42 at 3.5 hours.
What does a 13.0 kW system cost?
At a typical $2.50-$3.20 per watt installed: $32,407-$41,481 before incentives.