The Dominion threshold is not your threshold
Residential systems greater than 15 kW AC in Dominion Energy territory are subject to standby charges, with the amount depending on the peak power demand used on site. Appalachian Power and electric cooperative customers are not subject to demand charges.
That is a real difference in what a sensible system looks like. In Dominion territory 15 kW AC functions as a practical planning ceiling. Here the binding number is the statutory one: Virginia Code Section 56-594 compensates a residential system of not more than 25 kW one-to-one at the retail rate.
So read the name on your electricity bill before applying any Virginia sizing advice. Virginia is served by Dominion Energy, by Appalachian Power, and by a number of electric cooperatives, and guidance written for one does not transfer cleanly to the others.
It is also a fair test of an installer. Someone who works this part of Virginia will know that standby charges are a Dominion matter. Someone who opens by warning you about the 15 kW threshold has not done a project on your utility.
What actually constrains your design
Systems under Section 56-594 are typically sized not to exceed the customer's annual consumption, so your last twelve months of electricity bills are the right starting point rather than a generic household profile. Ask every installer to work from your actual bills and show the calculation.
Ask what percentage of your annual usage the proposed system covers. Without a standby charge cliff to design around, that consumption test and your available roof are the real constraints.
If your consumption is about to change, say so early. A heat pump, an electric vehicle or an additional occupant all move the number, and designing for a load you know is coming is easier than expanding later.
Net metering provisions have been under revision, so confirm the current terms with your utility before a design is finalised. That call is worth making yourself rather than relying on an installer summary.
Certificates, and why you can still sell them
The Virginia Clean Economy Act requires Appalachian Power to reach 100 percent renewable electricity by 2050 and Dominion Energy by 2045, and at least 1 percent of Dominion's requirement each year must come from in-state distributed generation resources smaller than 1 MW.
A useful consequence for you: a seller does not have to be a Dominion Energy or Appalachian Power customer to sell certificates into the Virginia market. So the market is open to you regardless of who bills you, including if a cooperative does.
To sell them you register your system and work with a broker. Certificates are eligible to be sold for 5 years, and prices move with the market rather than being set administratively.
Ask any installer what SREC price their projection assumes and where the figure came from, and ask to see the projection with certificate income removed entirely. That is your floor.
Ask your locality about the property tax exemption
Virginia Code Section 58.1-3661 allows any county, city or town to exempt or partially exempt certified solar energy equipment from local property taxes by adopting an ordinance. This is the detail most often got wrong about Virginia solar, because it is a local option rather than a statewide rule.
So a guide that tells you Virginia exempts solar from property tax is only right where the locality has actually adopted an ordinance, and it may be a partial exemption rather than a full one. Ask your county or city commissioner of the revenue directly whether an ordinance is in place and what it covers.
Where adopted, the exemption is effective beginning in the next succeeding tax year and is permitted for a term of not less than five years. Ask what term applies locally, since that is the horizon you can actually count on.
On the federal side, the 30 percent Residential Clean Energy Credit under Section 25D expired for property placed in service after December 31, 2025, so a cash or loan purchase now receives no federal credit. Section 48E survives at 30 percent for third-party owners under leases and power purchase agreements, so ask any such provider what they claim and what of that value reaches you, and confirm with a tax advisor.