How many solar panels for 1,500 kWh a month?
About 36 panels at 400 watts each, a 14.4 kW system, under the national-average 4.5 peak sun hours. Sun moves the count from 25 panels in the desert Southwest to 41 in the cloudiest states, and panel wattage trades count against roof area. Both tables below; your state in the picker.
Panel count by sun and wattage
Counts cover 1,500 kWh fully, rounded up to whole panels, with the 0.77 derate from rated watts to real output (methodology). Bold is the US-average column.
| Peak sun hours | 350W panels | 400W panels | 450W panels |
|---|---|---|---|
| 4.0 h | 46 | 41 | 36 |
| 4.5 h (US avg) | 41 | 36 | 32 |
| 5.0 h | 37 | 33 | 29 |
| 5.5 h | 34 | 30 | 26 |
| 6.0 h | 31 | 27 | 24 |
| 6.5 h | 29 | 25 | 22 |
Same bill, six real states
| State | Sun | Panels (400W) | System |
|---|---|---|---|
| Arizona | 6.5 h | 25 panels | 10 kW |
| Texas | 5.3 h | 31 panels | 12.4 kW |
| Florida | 5.2 h | 31 panels | 12.4 kW |
| Missouri | 4.6 h | 35 panels | 14 kW |
| New York | 3.9 h | 42 panels | 16.8 kW |
| Washington | 3.8 h | 43 panels | 17.2 kW |
What a 1,500 kWh household looks like
Fifteen hundred kWh a month is half again the national average: a big house, electric heat in a mild climate, a pool pump, or an EV on top of normal use. Arrays this size start to test roof space (about 36 panels at average sun, call it 756 sq ft), so higher-wattage panels earn their premium here, and a ground mount stops being a rural curiosity and starts being an option worth pricing.
Questions people ask
How many solar panels do I need for 1,500 kWh per month?
About 36 400-watt panels (a 14.4 kW system) at the national-average 4.5 peak sun hours, after the 0.77 real-world output derate. Strong desert sun brings it down to 25; cloudy-state sun pushes it to 41. The tables on this page break it out by sun figure and panel wattage.
What system size covers 1,500 kWh a month?
Roughly 14.2 kW of DC capacity at average US sun; we round panels up, so the quoted 14.4 kW covers it with a little margin. In sunnier states the same bill takes proportionally less capacity, which is the whole reason the per-state figures matter.
Do I have to cover 100% of the bill?
No, and often you shouldn’t. Utilities with poor net-metering rates make the last 20% of offset the worst-value panels on the roof, and some cap system size at your historical usage anyway. Sizing to 70-90% of the bill is a normal, defensible design choice; covering every kWh is only automatic where net metering pays retail.