How Many Solar Panels for 1,200 kWh per Month?
To cover 1,200 kWh per month you need about 11 kW of solar, or 28 panels of 400 W, assuming 4.5 peak sun hours a day. Depending on where you live that ranges from 21 panels (Southwest) to 36 panels (Northeast). The array needs roughly 588 sq ft of roof.
Solar panels for 1,200 kWh by region
| Region | Sun hours | System size | 400 W panels | Roof space |
|---|---|---|---|---|
| Northeast / Pacific Northwest | 3.5 | 14.09 kW | 36 | 756 sq ft |
| Midwest / Mid-Atlantic | 4.5 | 10.96 kW | 28 | 588 sq ft |
| Southeast / Texas | 5 | 9.86 kW | 25 | 525 sq ft |
| Southwest | 6 | 8.22 kW | 21 | 441 sq ft |
Based on 100% offset, 400 W panels and about 21 sq ft per panel. Peak sun hours are regional averages.
Cost of a 11 kW system
| Region | System size | At $2.50/W | At $3.00/W | At $3.50/W |
|---|---|---|---|---|
| Northeast / Pacific Northwest | 14.09 kW | $35,225 | $42,270 | $49,315 |
| Midwest / Mid-Atlantic | 10.96 kW | $27,397 | $32,877 | $38,356 |
| Southeast / Texas | 9.86 kW | $24,658 | $29,589 | $34,521 |
| Southwest | 8.22 kW | $20,548 | $24,658 | $28,767 |
Installed cost before any rebates. Cost is system watts × price per watt. The federal 25D credit ended for systems installed after December 31, 2025.
How it is calculated (4.5 sun hours)
1,200 kWh × 12 = 14,400 kWh per year (39.5 kWh per day)
14,400 ÷ (4.5 × 365 × 0.8) = 10.96 kW
10,959 W ÷ 400 W = 27.4 → 28 panels
28 × 21 sq ft = 588 sq ft of roof
Tips at 1,200 kWh per month
- Typical home range – This is close to an average US household. A 28-panel array (about 588 sq ft) usually fits on one or two roof planes.
- Panel wattage choice – Higher-wattage panels cut the count: at 450 W the same system needs about 25 panels instead of 28, which helps on smaller roofs.
- Batteries – Panels alone do not give backup power in an outage. A battery is sized separately and mainly pays off with time-of-use rates or poor net metering.
Frequently asked questions
How many solar panels do I need for 1,200 kWh per month?
About 28 panels of 400 W (10.96 kW) in a region with 4.5 peak sun hours. That ranges from 21 panels in the Southwest to 36 in the Northeast and Pacific Northwest.
How big a solar system do I need for 1,200 kWh a month?
1,200 kWh a month is 14,400 kWh a year. Divided by 4.5 sun hours × 365 days × 0.8 system efficiency, that gives a 10.96 kW system. It is 8.22 kW with 6.0 sun hours and 14.09 kW with 3.5.
How much does solar cost for 1,200 kWh per month?
At 4.5 sun hours the system costs about $27,397 to $38,356 installed ($2.50–$3.50 per watt), or $32,877 at $3.00. The federal 25D credit ended for systems installed after December 31, 2025, so check state and utility rebates separately.