How Many Solar Panels Does a 1,500 Sq Ft House Need?
Short answer: for a typical 1,500 sq ft home (about 675 kWh a month) you need roughly a 5.7–7.1 kW solar system — about 15–18 standard 400 W panels — in a typical climate with 4–5 peak sun hours a day. Sunnier regions need fewer panels; cloudier ones need more, and higher-wattage panels cut the count.
Panel count depends on your electricity use, not floor area. This assumes a 1,500 sq ft home uses about 675 kWh a month (≈ 0.45 kWh per sq ft) — your real usage may differ a lot, so check with your own bill.
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Panels needed for a 1,500 sq ft house, by sun hours
| Peak sun hours | System size | 400 W panels | 550 W panels |
|---|---|---|---|
| 3 h/day (cloudy / northern Europe) | 9.5 kW | 24 | 18 |
| 4 h/day (temperate (UK, parts of the US)) | 7.1 kW | 18 | 13 |
| 4.5 h/day (much of the US, southern Europe) | 6.3 kW | 16 | 12 |
| 5 h/day (Australia, South Asia, Mediterranean) | 5.7 kW | 15 | 11 |
| 6 h/day (desert / Middle East) | 4.7 kW | 12 | 9 |
Assumes a real-world performance ratio of 0.78 (inverter, wiring, heat and soiling losses). Find your local peak sun hours automatically in the calculator.
How we worked it out
The number of panels comes from three things: your monthly energy (675 kWh), your local peak sun hours, and each panel's wattage. The system size is monthly kWh ÷ (sun hours × 30.4 days × 0.78); the panel count is that system size divided by one panel's wattage. A 400 W panel at 4.5 sun hours makes about 1.40 kWh a day, so it takes roughly 16 of them to cover 675 kWh a month.
What changes your number
- Sun hours. The single biggest factor — see the range in the table above.
- Panel wattage. Moving from 400 W to 550 W panels cuts the count by roughly a quarter.
- Shading & roof pitch/orientation. Shade and a non-ideal tilt lower output, so you'd add panels.
- Self-consumption & net metering. Whether you use power as you make it — or export it — changes how much a given number of panels saves you.
Common questions
How many solar panels do I need for a 1,500 sq ft house?
Roughly 15–18 standard 400 W panels (a 5.7–7.1 kW system) in a typical climate with 4–5 peak sun hours a day. Sunnier locations need fewer; cloudier ones need more. Higher-wattage panels (e.g. 550 W) cut the count by roughly a quarter.
How much does one solar panel produce per month?
A standard 400 W panel produces roughly 1.40 kWh a day — about 43 kWh a month — at 4.5 peak sun hours, after real-world system losses.
How much roof space do I need for a 1,500 sq ft house?
About 31 m² (334 sq ft) of usable roof for a 400 W-panel array at ~4.5 sun hours. Steeper roof pitch, shading and obstructions change how much fits.
Will these panels fully offset my bill?
Not always. Panel count covers your energy (kWh), but your bill also depends on time-of-use, export/net-metering rules and fixed charges. Enter your own bill and location in the calculator for a payback and savings estimate.
Other ways to size your system
500 kWh/month 1,000 kWh/month 1,500 kWh/month 2,000 kWh/month 2,500 kWh/month 3,000 kWh/month 10 kWh/day 20 kWh/day 30 kWh/day 40 kWh/day 50 kWh/day 1,000 sq ft house 2,000 sq ft house 2,500 sq ft house 3,000 sq ft house
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