How Many Solar Panels Do I Need for 30 kWh per Day?
Short answer: to generate 30 kWh per day (about 912 kWh a month) you need roughly a 7.7–9.6 kW solar system — about 20–25 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.
30 kWh a day works out to roughly 912 kWh per month (× 30.4 days) — the figure the panel counts below are based on.
Get my exact number for my location →
Panels needed for 30 kWh a day, by sun hours
| Peak sun hours | System size | 400 W panels | 550 W panels |
|---|---|---|---|
| 3 h/day (cloudy / northern Europe) | 12.8 kW | 33 | 24 |
| 4 h/day (temperate (UK, parts of the US)) | 9.6 kW | 25 | 18 |
| 4.5 h/day (much of the US, southern Europe) | 8.5 kW | 22 | 16 |
| 5 h/day (Australia, South Asia, Mediterranean) | 7.7 kW | 20 | 14 |
| 6 h/day (desert / Middle East) | 6.4 kW | 17 | 12 |
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 (912 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 22 of them to cover 912 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 30 kWh a day?
Roughly 20–25 standard 400 W panels (a 7.7–9.6 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 30 kWh a day?
About 43 m² (463 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 40 kWh/day 50 kWh/day 1,000 sq ft house 1,500 sq ft house 2,000 sq ft house 2,500 sq ft house 3,000 sq ft house
Solar calculator by country
United States United Kingdom Australia India Pakistan South Africa Nigeria