The ZIPs around Allen hold about 4,700 single-family lots of an acre or more, though very few of them are inside the city itself — Allen is tightly platted and the acreage sits around it.
If you are on one of those lots, two local facts decide the job: which utility you are on, and how the city reads its own solar ordinance.
Before anything else, find out who sends your electric bill.
This corner of Collin County is split between the deregulated market and Grayson-Collin Electric Co-Op, and they pay very different things for the same exported kilowatt hour.
In most of the city you choose who bills you.
Oncor carries the power and owns the meter, but it buys none of your surplus.
Your retail provider sets the buyback and you can change providers when the contract ends.
On GCEC lines you cannot shop for a provider, and in exchange you get kilowatt-hour netting at the full retail rate — a rare thing in Texas now.
Every unit you send back takes a unit off your bill, and unused units bank for the following month.
Going solar moves you onto the distributed generation rate, which carries a $40 monthly base charge where the ordinary residential rate carries $25, plus a one-time $40 application fee.
The co-op is clear that a $40 minimum bill stands even in a month you over-generate.
Retail netting changes the ceiling: the extra production keeps its full value instead of dropping to an export rate, so on co-op lines the limit is your land rather than your own consumption.
Every North Texas provider's terms are on one page: what each utility pays for exported solar
Read Allen's solar ordinance closely.
As published, O-3846-8-21 permits solar panels on the roof of a primary structure or a permitted accessory structure such as a patio cover or storage building — wording that may simply not have contemplated a free-standing array on the ground.
We do not treat that as settled either way.
Before anything is filed for an Allen address we get the building department's reading of it in writing, along with what a ground mount is classed as for setbacks and height, and we tell you what they said.
Most of the acreage this page is written for is outside the city limits, and there the answer is simpler.
Texas counties have no general authority to require a building permit for ordinary single-family construction, and Collin County publishes none that reaches a residential array.
What still applies out there is septic setbacks, floodplain rules and the utility's interconnection approval.
Which is a real difference here: the same array can be a straightforward job on unincorporated land and an open question a mile away inside the city.
Allen is dark clay, and rock under it is common, not a surprise.
Close to three in ten of the points we checked around the city have bedrock inside three feet, and on the north side it is closer to four in ten.
We pulled the USDA soil survey at 113 points within six miles of Allen.
Ninety-four percent came back dark clay topsoil, half of it Houston Black clay, and about a fifth of the sample is Austin silty clay, which the survey puts on rock roughly thirty inches down.
Not one point came back sandy.
The clay swells when it is wet and shrinks when it dries, so the foundation reaches below the layer that moves.
Where rock is shallow, a driven pile stops early and the trench goes slower.
Both are ordinary work in Allen, and both are real numbers on the quote rather than surprises later.
On an acre there is normally more than one place the array could go, and your parcel's soil map helps decide which.
A south-facing array at the thirty degree tilt we build makes about 1,530 kWh a year for every kW installed at Allen's latitude.
That is roughly 15,300 kWh a year from a 10 kW system.
Points around the city ranged from about 1,518 to 1,559, so treat the city figure as a starting point and not a quote.
What it is worth depends on the meter.
On co-op lines the whole number earns the retail rate; on a retail plan the exported share earns whatever that plan pays.
Texas law stops an HOA banning solar outright, but lets it keep a ground mount inside a fenced yard and no taller than the fence. What an HOA can and cannot do
Inside Allen an association is close to certain — the city is a planned-subdivision city and most of the housing stock is modern.
On the acreage outside it, much less so.
Since we have not found an Allen ordinance capping ground-mount height, the association is usually the binding constraint on a city lot.
Where a fence line does govern, we bring the tilt down on the same frame until the array fits under it — about fourteen degrees puts four modules below six feet.
No holes in your roof, panels aimed south instead of wherever the house faces, and room to add panels when the load grows. Ground mount vs rooftop
Honestly: the published ordinance does not say clearly.
It permits panels on the roof of a primary structure or a permitted accessory structure such as a patio cover or storage building, which is roof-shaped language that may not have contemplated a free-standing array.
We get the building department's reading in writing before filing rather than assuming it either way, and we tell you what they said before you spend anything.
Usually, yes.
On unincorporated Collin County land there is no city ordinance to interpret and no county residential building permit, so what is left is septic setbacks, floodplain and the utility's interconnection approval.
Most of the acre-plus land in these ZIPs is outside the city limits anyway.
It changes the size more than the design.
On Grayson-Collin lines your export nets at the full retail rate, so a bigger array keeps its value.
On a retail plan on Oncor's lines the exported share is worth whatever your plan pays, so the array wants sizing closer to your own use.
Your bill names the company.
Four hundred to six hundred square feet for a normal house, which on an acre is a corner of the lot.
The constraint is almost never space — it is how far the array sits from your meter, because the trench between them is priced by the foot.
The towns nearest yours with a page of their own.
No salesman. No home visit to get a number.
