How many solar panels for 750 kWh a month?
About 18 panels at 400 watts each, a 7.2 kW system, under the national-average 4.5 peak sun hours. Sun moves the count from 13 panels in the desert Southwest to 21 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 750 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 | 23 | 21 | 18 |
| 4.5 h (US avg) | 21 | 18 | 16 |
| 5.0 h | 19 | 17 | 15 |
| 5.5 h | 17 | 15 | 13 |
| 6.0 h | 16 | 14 | 12 |
| 6.5 h | 15 | 13 | 11 |
Same bill, six real states
| State | Sun | Panels (400W) | System |
|---|---|---|---|
| Arizona | 6.5 h | 13 panels | 5.2 kW |
| Texas | 5.3 h | 16 panels | 6.4 kW |
| Florida | 5.2 h | 16 panels | 6.4 kW |
| Missouri | 4.6 h | 18 panels | 7.2 kW |
| New York | 3.9 h | 21 panels | 8.4 kW |
| Washington | 3.8 h | 22 panels | 8.8 kW |
What a 750 kWh household looks like
Seven hundred fifty kWh is just under the national average, typical of a mid-size home with gas heat or a careful all-electric household. It is a sweet spot for rooftop solar: the array fits on almost any south-facing roof with room to spare, and no exotic equipment is involved. The marginal cost of a couple more panels is low while the crew is already on the roof; if the quote comes back with spare roof area, ask what two more panels change.
Questions people ask
How many solar panels do I need for 750 kWh per month?
About 18 400-watt panels (a 7.2 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 13; cloudy-state sun pushes it to 21. The tables on this page break it out by sun figure and panel wattage.
What system size covers 750 kWh a month?
Roughly 7.1 kW of DC capacity at average US sun; we round panels up, so the quoted 7.2 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.