Process, step 1
What a Solar Site Assessment Covers
A solar site assessment is the visit where we measure the roof, open the electrical panel, and read a year of bills, so the proposal fits your house instead of a satellite photo. It is free, and it ends with a written proposal.
Reviewed 2026-09-24
Google reviews
1,463 across four profiles
Family-owned
Since 1996
Licensed and insured
VA 2705031092
On every install
Master electrician on site
Backed by
Workmanship warranty
Answer first
The short answer
A solar site assessment checks four things: the roof, the electrical service, your usage, and the paperwork path. We do all four in one visit because the electrical side decides as much of the price as the roof does.
- Roof: age, pitch, direction, structure, and shade. Fairfax County's own guidance calls six or more hours of direct sun ideal, with south and west faces best.
- Electrical: service size, panel busbar and main breaker ratings, grounding, the meter base, and where the solar connection can legally land.
- Usage: twelve months of bills, because Dominion caps a net metered system at what should produce about 150 percent of expected annual use.
- Paperwork: the permit office, the utility, and any HOA review, confirmed from the parcel and the bill.
The roof: sun, age, and structure
Fairfax County tells homeowners that six or more hours of direct sun a day is ideal, that a south or west face gets the most exposure, and that a roof going under an array should be less than five years old because an installation lasts 20 to 25 years. We check all three on the visit, not from a map.
Shade is measured, then modeled. The NOVA Solar Map and the PVWatts calculator give a first read on a roof, and we confirm it on site against the actual trees and chimneys. Every production number we hand you is a modeled estimate, labeled that way on the proposal.
In the attic we look at rafter or truss size, spacing, and condition. Fairfax County accepts either drawings that meet its minimum submission requirements or the county's typical details, and the framing tells us which one fits your roof.
The electrical side a salesperson skips
This is the part of the visit an electrical contractor does best, and it is where most surprise change orders come from on other companies' jobs. We open the panel and read the labels before anyone counts modules.
Virginia's interconnection rule says the solar capacity at a service location has to stay below the capacity of the utility's service drop and service entrance cable, unless the customer pays for the upgrade. Dominion also requires the solar to connect on the customer side of the meter, never inside the meter cabinet without Dominion's approval. Both rules make the service entrance part of the assessment.
- Service size: 100A and 150A services often need a heavy-up before a backfed breaker fits. The heavy-up is priced on the same proposal at the published $3,500–$7,500 range.
- Busbar and main breaker: the 120 percent rule limits how large a backfed solar breaker can be on a given panel.
- Grounding and bonding: the array's grounding has to match the utility's grounding scheme, so we check the existing electrode and bonding first.
- Future loads: an EV charger, a heat pump, or a battery changes the load calculation, so we plan them now.
Your bills set the size
Virginia's net metering statute covers residential systems up to 25 kW, and Dominion requires that a system not reasonably produce more than 150 percent of the home's expected annual use. We size to twelve months of bills, then check the roof can hold it.
A typical home array is 8 to 12 kW, which prices at $19,000–$34,000 installed at $2.40–$2.85/W. Our published points are $19,200–$22,800 for 8 kW, $24,000–$28,500 for 10 kW, and $28,800–$34,200 for 12 kW.
If you plan an electric vehicle or a heat pump, bring that up at the visit. The array can be sized for the load you will have, as long as it stays inside the utility's cap.
Permit office, utility, and HOA
The mailing address does not settle the permit office. In Fairfax County, Land Development Services issues the residential solar permit, but projects inside the towns of Vienna and Clifton need the town's approval uploaded to the county record first. We confirm the jurisdiction from the parcel.
The utility comes from the bill. Homes in our area are served by Dominion Energy Virginia, by NOVEC, whose territory includes Fairfax, Loudoun, and Prince William counties, the City of Manassas Park, and the Town of Clifton, or, inside the City of Manassas, by the city's own electric department. The interconnection form is different for each.
If your home is in an association, Virginia Code 55.1-1820.1 limits what it can restrict on your own roof. We note the association on the visit so the HOA package is ready before the permit.
How the visit runs
The assessment is free and there is no dispatch fee on it. It runs in this order.
- 01
Before we arrive
Send twelve months of electric bills and the property address. We pull the parcel record and aerial imagery.
- 02
Outside
Roof faces, pitch, obstructions, and tree shade, plus the meter base and service drop.
- 03
Inside
The panel, main breaker, busbar rating, grounding, and the attic framing under the planned array.
- 04
The written proposal
System size, a modeled production estimate, the cash price, and separate lines for any panel, battery, or EV charger work.
Straight answers
Questions
- Is the solar site assessment free?
- Yes. The assessment and the written proposal are free, and the dispatch fee never applies to an estimate. You get the numbers in writing whether or not you move ahead.
- Do I need to be home for the site assessment?
- Yes, for the inside part. We need to open the electrical panel and look in the attic, and both need you there. The roof and meter check happen from outside.
- What if my panel is too small for solar?
- Then the proposal includes the heavy-up, priced on the same page at the published $3,500–$7,500 range. Doing both in one job means one permit sequence, one inspection plan, and one crew.
- Is the production number on the proposal a promise?
- No. It is a modeled estimate from your roof, your shade, and standard weather data, and it is labeled that way. Actual output moves with weather and shade from year to year.
- What if the roof is too shaded?
- We say so and show the modeled numbers. A ground mount, a smaller array on the one clear face, or a battery and generator hookup plan may be the better proposal for that property.
Sources
- Fairfax County Office of Environmental and Energy Coordination, Going Solar
- Dominion Energy Virginia, Net Metering
- Virginia Administrative Code 20VAC5-315-40, Conditions of interconnection
- Code of Virginia 56-594, Net energy metering provisions
- Fairfax County Land Development Services, Solar (SOLARR) Residential
- Code of Virginia 55.1-1820.1, Installation of solar energy collection devices
- NOVEC, At a Glance (service territory)
- National Laboratory of the Rockies, PVWatts Calculator
- Northern Virginia Regional Commission, NOVA Solar Map
Next step
Book a free solar site assessment
A master electrician is on site for every solar project, and the assessment is where that starts. Send your bills and address and we will schedule the visit.
Solar energy company
AJ Long Electric Solar
AJ Long Electric
7138 Little River Turnpike #305
Annandale, VA 22003
Serving Annandale, Fairfax County, and Northern Virginia.