In Wilmington your electric utility is Delmarva Power, and solar earns full retail net metering on systems up to 25 kW. A typical 7 kW Wilmington roof makes about 9,546 kWh a year (MySolarFY analysis, August 2026). Delaware charges no sales tax on the equipment. The 30% federal homeowner credit ended December 31, 2025.
Wilmington is Delaware’s largest city, and rooftop solar works differently here than the brochures written for the suburbs suggest. Your power comes from Delmarva Power, your permit comes from the City of Wilmington, and a lot of the city’s homes are older brick rowhomes with smaller, partly shaded roofs. This page covers the parts that are actually local: who your utility is, what a Wilmington roof produces, how the city permits a rooftop system, and how to read a quote when your house is a century old. For the deep mechanics of Delmarva’s net metering and Delaware’s Green Energy Program grant, we point you to the pages that cover them in full so this one can stay about Wilmington.
Who provides your power in Wilmington
Wilmington sits in New Castle County, and the regulated electric utility across the city is Delmarva Power, an Exelon company that serves about 312,000 electric customers in Delaware (OpenEI utility profile). Delmarva is the interconnection authority for a home solar system in Wilmington, which means Delmarva reviews your application, sets the bidirectional meter, and issues the Permission to Operate before your panels can run on the grid. This matters because Delaware also has customer-owned electric utilities elsewhere in the state, the Delaware Electric Cooperative and several municipal systems, whose solar programs are not the same as Delmarva’s. In Wilmington proper you are a Delmarva customer, so confirm any program you read about is the Delmarva Delaware version.
| Detail | What to know in Wilmington |
|---|---|
| Electric utility | Delmarva Power, the regulated utility for New Castle County and the interconnection authority for your solar system |
| Electric rate | Delaware residential power averages about 19.4 cents per kWh (EIA Electric Power Monthly, Table 5.6.A, May 2026), just above the national average of about 18.4 cents |
| Net metering | Full retail credit on residential systems up to 25 kW, with credits that roll forward month to month |
| Typical roof output | About 9,546 kWh a year from a 7 kW system in ZIP 19801 (NREL PVWatts v8), before shading losses common on older city roofs |
| City permit | The City of Wilmington Department of Licenses and Inspections issues the building and electrical permit, separate from the county |
| Sales tax | Delaware charges no statewide sales tax, so there is none on your solar equipment |
What a Wilmington roof actually produces
A typical Wilmington home makes a little under 10,000 kWh a year from a normal-sized system, which offsets most of an average bill.
Here is our own estimate for a Wilmington address. According to MySolarFY’s analysis (August 2026), a typical 7 kW rooftop system in Wilmington ZIP 19801 produces about 9,546 kWh a year (NREL PVWatts v8), which offsets roughly $1,850 of grid power at Delaware’s 19.4 cents per kWh. That is the clean-sky number. Wilmington’s older neighborhoods carry a lot of mature street trees and tightly spaced rowhomes, so real roofs here often lose output to afternoon shade and to north-facing or broken-up roof planes. A shorter, steeper city roof also fits fewer panels than a wide suburban ranch. Treat 9,546 kWh as a ceiling for a clear, well-oriented roof and ask an installer to model your specific address with a shade analysis. To see how the bill credit lowers your monthly cost, read how solar lowers your electricity bill.
| System size | Estimated output, ZIP 19801 | Grid power offset at 19.4 cents per kWh |
|---|---|---|
| 5 kW | About 6,818 kWh a year | About $1,320 a year |
| 7 kW | About 9,546 kWh a year | About $1,850 a year |
| 10 kW | About 13,636 kWh a year | About $2,645 a year |
MySolarFY estimates from NREL PVWatts v8 for ZIP 19801, a clear standard-tilt roof, August 2026. Real output is lower with shading, and the offset uses Delaware’s average residential rate. Your figures depend on your roof, orientation, and usage.
See which solar programs are available at your Wilmington address
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Permitting solar in the City of Wilmington
Inside city limits, your permit is a City of Wilmington permit, not a New Castle County one. Rooftop solar in Wilmington is reviewed by the City of Wilmington Department of Licenses and Inspections, which issues the building and electrical permit and inspects the finished work for code compliance (City of Wilmington Licenses and Inspections). Applications are handled through the Department of Land Use and Planning at 800 North French Street. The practical order for a Wilmington install looks like this:
- City permit. Your installer files the building and electrical permit with City of Wilmington Licenses and Inspections and the work is reviewed against the current adopted electrical code.
- Delmarva interconnection. In parallel, the installer files the interconnection application with Delmarva Power for a system up to 25 kW.
- Install and city inspection. The system is installed and passes the City of Wilmington electrical inspection.
- Meter set. Delmarva Power installs a bidirectional net meter that measures both delivered and exported energy.
- Permission to Operate. Delmarva issues Permission to Operate. The system may not run on the grid before this.
If your rowhome is in one of Wilmington’s historic districts, expect an added design-review step before the permit, so ask your installer to confirm whether your block carries a historic overlay. A licensed installer normally manages the whole permit and interconnection process for you. For the questions to ask before you sign, see the right questions to ask a solar installer.
Wilmington’s older housing, and what it means for a quote
Much of Wilmington’s housing stock predates the war, from Trinity Vale and Cool Spring rowhomes to the larger homes off Delaware Avenue. That age shapes a solar quote in three ways worth knowing before you compare bids:
- Roof condition first. Panels last 25 years or more, so an aging city roof often needs to be replaced or reinforced before the array goes on. Get the roof assessed up front so the cost is in the quote, not a surprise later.
- Smaller, shaded roof planes. A narrow rowhome roof, dormers, and mature street trees mean fewer usable panels and lower output than a suburban roof, which is why the shade analysis in the quote matters more here.
- Electrical service upgrades. Older Wilmington homes sometimes run a smaller or dated electrical panel that needs upgrading to add solar safely, another line item to confirm in writing.
None of this means solar does not pay in the city; it means a Wilmington quote should be built around your actual roof and panel, not a generic template. That is exactly what a real local site visit is for.
Incentives and net metering, in brief
The money side of Wilmington solar is the Delaware money side, and it is genuinely good. You get full retail net metering from Delmarva on a system up to 25 kW, credits roll forward month to month, and Delaware’s Green Energy Program pays Delmarva residential customers an up-front grant of $0.80 per watt, capped at a $10,000 grant (Delaware DNREC Green Energy Program, effective July 1, 2026). There is no state sales tax on the equipment either. Because those programs are set at the state and utility level rather than by the city, we keep the full mechanics on two dedicated pages: read how Delmarva Power solar and the Green Energy Program work in Delaware for the grant rules and the SREC trade-off, and see the Delaware solar overview for the statewide picture. For a plain-English primer on export credits, see how net metering credits your solar exports, and our guide to solar incentives for the wider list.
What changed federally, and what it means in Wilmington
The federal homeowner credit is gone, but Delaware’s incentives are not. The 30% federal Residential Clean Energy Credit (Section 25D) ended for systems placed in service after December 31, 2025, under the One Big Beautiful Bill Act, so a Wilmington homeowner who buys solar with cash or a loan in 2026 cannot claim it (IRS Residential Clean Energy Credit; SEIA). Delmarva net metering, the Delaware Green Energy Program grant, and the state’s zero sales tax were not affected, and at Delaware’s rates the bill offset plus the grant still carry the math. A separate commercial credit, Section 48E, is claimed by the business that owns a leased or PPA system, not by the homeowner. For the full timeline, see what the federal solar tax credit change means in 2026.
How to choose a solar installer in Wilmington
Rather than chasing a “best installer” list, screen any company that quotes your Wilmington roof against objective criteria:
- NABCEP certification, the industry’s professional standard for PV installers.
- Proper Delaware licensing plus a City of Wilmington building and electrical permit, not a county one.
- Real experience with Delmarva Power interconnection and the Delaware Green Energy Program paperwork, so your grant and Permission to Operate go smoothly.
- An honest read on your older roof and electrical panel, with any replacement or upgrade priced in the written quote.
- A written production estimate that accounts for your roof’s real shading, not a generic clear-sky figure. For a checklist, see the right questions to ask a solar installer.
MySolarFY matches you with licensed installers that serve the Wilmington area so you can compare real local quotes side by side, with no obligation.
Frequently asked questions
Who is my electric utility in Wilmington, Delaware?
Delmarva Power. Wilmington is in New Castle County, where Delmarva Power is the regulated electric utility and the interconnection authority for home solar, so Delmarva reviews your application, sets the net meter, and issues Permission to Operate before your panels can run. Delaware also has the Delaware Electric Cooperative and several municipal utilities elsewhere in the state, but in Wilmington proper you are a Delmarva customer, so make sure any program you read about is the Delmarva Delaware version.
How much power does a solar system produce in Wilmington?
According to MySolarFY’s analysis (August 2026), a typical 7 kW rooftop system in Wilmington ZIP 19801 produces about 9,546 kWh a year on a clear, well-oriented roof (NREL PVWatts v8), which offsets roughly $1,850 of grid power at Delaware’s 19.4 cents per kWh. That is a clear-sky estimate. Wilmington’s mature street trees, tightly spaced rowhomes, and smaller roof planes often reduce real output, so treat this as a ceiling and ask an installer to model your address with a shade analysis.
Who issues the solar permit in Wilmington?
The City of Wilmington Department of Licenses and Inspections issues the building and electrical permit for a rooftop system inside city limits, and it inspects the finished work, separate from New Castle County. Applications are handled through the Department of Land Use and Planning at 800 North French Street. If your home sits in a historic district, expect an added design-review step first. Your licensed installer normally handles the permit and the Delmarva interconnection together.
What incentives can a Wilmington homeowner get?
You get full retail net metering from Delmarva Power on a system up to 25 kW with credits that roll forward, plus Delaware’s Green Energy Program grant of $0.80 per watt, capped at a $10,000 grant, for Delmarva residential customers (Delaware DNREC, effective July 1, 2026). Delaware also has no state sales tax on the equipment. The 30% federal homeowner credit (Section 25D) ended December 31, 2025, so most 2026 buyers cannot claim it. The full grant rules live on our Delmarva Power Delaware page.
Does the older housing in Wilmington make solar harder?
It changes the quote more than it changes whether solar pays. Many Wilmington homes are older brick rowhomes with smaller, partly shaded roofs and sometimes a dated electrical panel, so a good quote should price any needed roof or panel work up front and base production on your roof’s real shading, not a generic figure. A proper local site visit and shade analysis is how a reputable installer handles this.
Do I qualify for the Green Energy Program grant if I lease or sign a PPA?
The residential Green Energy Program grant is for owned systems, so a residential lease or PPA does not receive that grant, and on a lease or PPA the company that owns the panels typically keeps the net-metering credits and any certificates while your benefit is a lower or fixed power price with no up-front cost. If you want the grant, the net-metering value, and the certificates in your own name, owning the system through cash or a loan is the path that captures them. See our Delmarva Power Delaware page for the full grant rules.
Reviewed by the MySolarFY team. Figures were verified against the linked Delaware (Delmarva Power, Delaware DNREC), City of Wilmington, DSIRE, EIA, NREL PVWatts, and IRS sources as of August 2026; electric rates, the Green Energy Program grant schedule, and net-metering terms all move over time, so confirm current terms with Delmarva Power, the City of Wilmington, and Delaware DNREC before you decide. Production figures are NREL PVWatts v8 estimates for a clear roof and will be lower with shading. MySolarFY does not provide tax or financial advice; consult a licensed professional about your own situation. Learn more about the MySolarFY team and how we work.
MySolarFY is a free service that matches homeowners with licensed solar installers. We are not an installer, financing company, or government program. “No up-front cost” refers to qualifying lease or PPA financing, where eligible homeowners may have no out-of-pocket cost at installation. Lease and PPA terms typically run 20 to 25 years, may include an annual price escalator, and total payments may exceed the cost of a cash purchase; on a lease or PPA the certificates and bill credits often go to the company that owns the system, not the homeowner, and the residential Green Energy Program grant does not apply. Homeowners do not get the federal residential credit that ended after December 31, 2025. Solar panels are not free and monthly payments apply. Eligibility, savings, incentives, and rates vary and are not guaranteed. See our full disclaimer.
