How many solar panels for a 1,200 square foot house?
Floor area is a proxy, not a meter. This page is for a 1,200 sq ft home, not a 1,200 kWh monthly bill. We assume 680 kWh a month for a typical home this size (gas heat, normal AC), which lands at 17 panels of 400W (6.8 kW) under average US sun. Homes this size honestly swing from about 500 kWh (12 panels) to 950 kWh (23 panels). If you already have bills, skip this page and use the calculator or the matching 750 kWh per month page; if you are sizing a house you have not moved into yet, stay here and read the band.
Usage variance at 1,200 sq ft
This is the table house-size searches actually need: three usage bands for the same footprint, each turned into 400W panel counts at desert, average, and cloudy sun. The middle row is this page's planning figure.
| Usage band for this size | Monthly kWh | Panels @ 4.5 h | @ 6.5 h desert | @ 4.0 h cloudy |
|---|---|---|---|---|
| Efficient (gas heat, careful use) | 500 kWh/mo | 12 | 9 | 14 |
| Typical (this page's assumption) | 680 kWh/mo | 17 | 12 | 19 |
| Heavy (all-electric or big AC/EV loads) | 950 kWh/mo | 23 | 16 | 26 |
Sun alone, at the typical 680 kWh assumption, moves the count from 12 panels in the desert Southwest to 19 in the cloudiest states. Pick your state in the tool; or start from the peak sun hours by state table if you only have a location so far.
Why 680 kWh for this size
Starter homes and older bungalows. At this size one big load dominates: a window-AC summer or a space-heater winter shows up as a 30% swing on the monthly total, which is why a 12-month average matters more here than on bigger houses where loads cancel each other.
Houses in this range are frequently old enough to still be on 100-amp service, and that is worth checking before anything else. A 100-amp panel leaves far less room for a backfed solar breaker than a 200-amp one, and on an older load center there may be no spare double-pole space at all. Sometimes the answer is a small main-breaker derate rather than a full service upgrade, which is a conversation for whoever does the site survey. None of it has anything to do with 1,200 square feet and all of it has to do with the decade that built them.
If your bill differs, re-run the count at the real number rather than averaging floor plans. Rough rule after the 0.77 derate: about two 400W panels per extra 100 kWh/mo at 4.5 peak sun hours. Worked bill tiers live on the 750 kWh page and the situations hub.
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 if the home uses about 680 kWh a month, our typical figure for this size. Efficient homes at ~500 kWh need about 12 panels; heavy-use homes at ~950 kWh need about 23. Square feet are a proxy. Twelve months of bills beat any floor-area table.
How much electricity does a 1,200 sq ft house use?
We plan on 680 kWh a month as typical, with a working band of about 500 to 950 depending on heat fuel, AC, and lifestyle. The midpoint is scaled from EIA's ~900 kWh national household average with usage growing slower than floor area. All-electric resistance heat can blow past the high end in winter climates.
What if my bill is different from the assumption?
Use the real number. Drop your monthly kWh into the main calculator, or open the nearest bill page (750 kWh/mo) if you want a fixed-usage walkthrough. Every extra 100 kWh a month is roughly two 400W panels at average US sun after the 0.77 derate.
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.
Will a house this old need an electrical service upgrade?
Sometimes, and it is worth checking early. Homes in this size range are often still on 100-amp service, where a backfed solar breaker has much less room inside the busbar allowance than it would on a 200-amp panel, and older load centers may have no spare double-pole space at all. A modest main-breaker derate is often enough to avoid a full upgrade. The site survey answers it; the square footage never will.