How Many Solar Panels for 3,000 kWh per Month?
To cover 3,000 kWh per month you need about 27.4 kW of solar, or 69 panels of 400 W, assuming 4.5 peak sun hours a day. Depending on where you live that ranges from 52 panels (Southwest) to 89 panels (Northeast). The array needs roughly 1,449 sq ft of roof.
Solar panels for 3,000 kWh by region
| Region | Sun hours | System size | 400 W panels | Roof space |
|---|---|---|---|---|
| Northeast / Pacific Northwest | 3.5 | 35.23 kW | 89 | 1,869 sq ft |
| Midwest / Mid-Atlantic | 4.5 | 27.4 kW | 69 | 1,449 sq ft |
| Southeast / Texas | 5 | 24.66 kW | 62 | 1,302 sq ft |
| Southwest | 6 | 20.55 kW | 52 | 1,092 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 27.4 kW system
| Region | System size | At $2.50/W | At $3.00/W | At $3.50/W |
|---|---|---|---|---|
| Northeast / Pacific Northwest | 35.23 kW | $88,063 | $105,675 | $123,288 |
| Midwest / Mid-Atlantic | 27.4 kW | $68,493 | $82,192 | $95,890 |
| Southeast / Texas | 24.66 kW | $61,644 | $73,973 | $86,301 |
| Southwest | 20.55 kW | $51,370 | $61,644 | $71,918 |
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)
3,000 kWh × 12 = 36,000 kWh per year (98.6 kWh per day)
36,000 ÷ (4.5 × 365 × 0.8) = 27.4 kW
27,397 W ÷ 400 W = 68.49 → 69 panels
69 × 21 sq ft = 1,449 sq ft of roof
Tips at 3,000 kWh per month
- Plan for a ground mount – 69 panels need about 1,449 sq ft – more than most residential roofs offer. A ground mount, carport or partial offset (for example 70%) are common solutions.
- Utility limits – Large systems may hit utility interconnection caps or need a main-panel upgrade. Ask your utility about the maximum system size allowed before getting quotes.
- Batteries – Batteries are sized separately from panels. At this usage, backing up the whole home is expensive; most owners back up essential circuits with one or two batteries.
Frequently asked questions
How many solar panels do I need for 3,000 kWh per month?
About 69 panels of 400 W (27.4 kW) in a region with 4.5 peak sun hours. That ranges from 52 panels in the Southwest to 89 in the Northeast and Pacific Northwest.
How big a solar system do I need for 3,000 kWh a month?
3,000 kWh a month is 36,000 kWh a year. Divided by 4.5 sun hours × 365 days × 0.8 system efficiency, that gives a 27.4 kW system. It is 20.55 kW with 6.0 sun hours and 35.23 kW with 3.5.
How much does solar cost for 3,000 kWh per month?
At 4.5 sun hours the system costs about $68,493 to $95,890 installed ($2.50–$3.50 per watt), or $82,192 at $3.00. The federal 25D credit ended for systems installed after December 31, 2025, so check state and utility rebates separately.