How many solar panels for a 1,200 sq ft house?
About 17 panels at 400 watts (6.8 kW), assuming the 680 kWh a month typical of a 1,200 sq ft home and average US sun. But hear the assumption creak: houses don't use electricity, habits do. If you have actual bills, feed those to the calculator and skip the proxy; if you're sizing a house you haven't moved into yet, this page is the right tool.
Panel count by sun and wattage
At the assumed 680 kWh a month, rounded up, 0.77 derate applied. Bold is the US-average column.
| Peak sun hours | 350W panels | 400W panels | 450W panels |
|---|---|---|---|
| 4.0 h | 21 | 19 | 17 |
| 4.5 h (US avg) | 19 | 17 | 15 |
| 5.0 h | 17 | 15 | 13 |
| 5.5 h | 16 | 14 | 12 |
| 6.0 h | 14 | 13 | 11 |
| 6.5 h | 13 | 12 | 10 |
The same house, six real states
| State | Sun | Panels (400W) | System |
|---|---|---|---|
| Arizona | 6.5 h | 12 panels | 4.8 kW |
| Texas | 5.3 h | 14 panels | 5.6 kW |
| Florida | 5.2 h | 14 panels | 5.6 kW |
| Missouri | 4.6 h | 16 panels | 6.4 kW |
| New York | 3.9 h | 19 panels | 7.6 kW |
| Washington | 3.8 h | 20 panels | 8 kW |
About the 680 kWh assumption
Starter homes and older bungalows. At this size one big load dominates the bill: a window-AC summer or a space-heater winter shows up as a 30% swing, which is why the 12-month average matters more here than anywhere.
Questions people ask
How many solar panels does a 1,200 sq ft house need?
About 17 400-watt panels (6.8 kW) at average US sun, assuming the 680 kWh a month typical of that size; 12 panels in the sunniest states, 19 in the cloudiest. If you have 12 months of bills, use those instead: square feet are a proxy, kWh are the truth.
How much electricity does a 1,200 sq ft house use?
We assume 680 kWh a month, scaled from EIA's ~900 kWh national household average with usage growing slower than floor area. Heating fuel is the big swing: this figure fits gas heat, and all-electric resistance heat can add 50% or more in winter climates.
Will the panels fit on the roof?
17 panels want about 357 sq ft of usable, unshaded roof once racking gaps are counted, and a 1,200 sq ft single-story home has roughly its footprint in gross roof, less pitch effects, vents, setbacks, and the north face. Usually yes on a simple gable, tight on complex roofs. Two-story homes have half the footprint to work with.