The panel we fit is 44.7 by 67.8 inches. That is 21.05 square feet of panel, and at 435 watts each it takes 2.3 of them to make a kilowatt.
So a kilowatt of panel is about 48 square feet of glass.
That is not the number you want, because the panels do not lie flat.
We build one continuous table, four panels high in landscape, at a thirty degree tilt. There are no gaps between rows, because there is only one row — four panels deep up the slope rather than four separate rows with spacing between them.
Four panels up the slope is just under fifteen feet of panel. Tilted at thirty degrees, that lands on thirteen feet of ground.
Which means the ground footprint is smaller than the panel area, not bigger: about 42 square feet of ground per kilowatt installed. Tilting a panel shrinks its shadow on the plan.
| Array | Array footprint | Ground per kW |
|---|---|---|
| 20 panels · 8.7 kW | about 28 ft × 13 ft, 367 sq ft | 42 sq ft |
| 24 panels · 10.4 kW | about 34 ft × 13 ft, 441 sq ft | 42 sq ft |
| 28 panels · 12.2 kW | about 40 ft × 13 ft, 514 sq ft | 42 sq ft |
| 36 panels · 15.7 kW | about 51 ft × 13 ft, 661 sq ft | 42 sq ft |
That is where “four hundred to six hundred square feet for a normal house” comes from. It is not a rule of thumb. It is the panel, the racking and the tilt, multiplied out.
Nobody installs an array in a box exactly its own size. We clear fifteen feet of working room around it, which is what the machinery needs and what stops the grass growing into the back row.
On a ten kilowatt system that turns 441 square feet of array into about 2,750 square feet of cleared ground — still only a sixteenth of an acre, but seven times the array itself.
If the spot has trees or heavy brush, that cleared area is what gets priced: $1,500 for mobilisation and the first quarter acre, then $2,500 an acre after that. What ground mount solar costs in Texas
An acre is 43,560 square feet, and the array wants a sixteenth of it. So on paper an acre is enormous. In practice four things eat it.
The house and everything around it. The setbacks — Southlake keeps a ground mount ten feet off any side or rear line, Celina applies its accessory-structure setbacks and keeps it out of the front yard entirely.
Shade, which is measured in December at four in the afternoon rather than in June at noon. And the run back to your meter, priced by the foot, which is usually what decides between two otherwise equal spots.
What is left after those four is rarely the whole acre. It is normally still plenty.
Under about an acre we usually say no, and we would rather say it on the phone than after a survey.
It is not the array's footprint that fails. It is everything around it: the setbacks take a strip off each boundary, the neighbour's house shades the southern edge on a small lot, and the sensible spot ends up so close to the property line that the array is either non-compliant or in the wrong place for sun.
There are exceptions and they are shaped like a long thin lot with a clear southern edge. Put the address in the design tool and it will tell you what fits before anybody visits.
About 42 square feet of ground per kilowatt with our racking — four panels high in landscape at a thirty degree tilt.
The panels themselves are about 48 square feet per kilowatt, and the footprint is smaller than that because tilting them shrinks their shadow on the plan.
Add fifteen feet of working room on every side and a ten kilowatt array occupies about 2,750 square feet of cleared ground, against 441 square feet of array.
Under about an acre, usually not.
The array itself fits — a house-sized system is four hundred to six hundred square feet.
What does not fit is the array plus the setbacks plus the working room plus a clear view south, once the house and the neighbour's roofline have taken their share.
That is a judgement about your particular lot rather than a rule, and the design tool makes it from your own address in about three minutes.
Ours normally is: one continuous table, four panels high.
It is the cheapest arrangement because it puts the most panels on the fewest foundations, and it is the shortest run of racking.
Splitting it into two tables is possible where the ground forces it, and it costs more — more foundations, more racking, and a longer electrical run tying them together.
Almost certainly less than you think, and the limit is rarely land.
Covering a typical North Texas house takes something in the eight to fifteen kilowatt range, which is 367 to 661 square feet of array.
What limits the size on acreage is usually the trench back to your meter and, on some utilities, what your co-op pays for exported power.
Both are worth settling before anybody talks about panel count.
No salesman. No home visit to get a number.
