Solar panels in Wilmington, DE: cost and payback (2026)
Solar panels in Wilmington cost about $23,200 installed for an 8 kW system, and $20,700 net. There is no federal homeowner credit in that figure — the 30% credit ended for systems placed in service after December 31, 2025. At 16.5¢ per kWh that system offsets roughly $141 a month and pays itself back in 12.2 years — assuming Delmarva Power, which serves most of Wilmington, credits what you export.
Cost, rate and sun hours are Delaware statewide figures from EIA and NREL — we do not publish a separate Wilmington rate or sun-hour value we cannot source. The utility is the part that is genuinely local, and it is the part that changes the answer most. Incentives are modelled for today’s date, so nothing expired is counted.
Delmarva Power: what it means for solar in Wilmington
Delmarva Power serves most of Wilmington. It is investor-owned utility — regulated by the state public utility commission, so the statewide net metering or net billing rule below is the one that applies to you, and any change to it goes through a public docket you can read.
Because Delmarva Power answers to the state commission, the Delaware rule is the one that governs your exports: Delaware has full retail net metering with annual true-up, and homeowners can also sell SRECs into the state's compliance market.
Whichever it is, this is the first question to settle and the one installers are least specific about. Ask for the rider or tariff name, the per-kWh export credit, how long that credit is locked for, and the current interconnection turnaround — in the written quote, not in conversation. Service territories cut across city limits, so confirm against the name at the top of your own bill.
Cost by system size in Wilmington
Within one city, quotes still spread. A steep or cut-up roof costs more in labour than a simple south-facing plane. A main service panel at capacity adds a four-figure upgrade before a single module goes up. Two storeys costs more than one. None of that shows up in a per-watt average, which is why the table below is a starting point rather than a quote.
| System | Panels | Gross cost | State incentive | Net cost | Yr 1 savings | Payback |
|---|---|---|---|---|---|---|
| 6 kW | 15 | $17,400 | −$2,500 | $14,900 | $1,272 | 11.7 yrs |
| 8 kW | 20 | $23,200 | −$2,500 | $20,700 | $1,696 | 12.2 yrs |
| 10 kW | 25 | $29,000 | −$2,500 | $26,500 | $2,120 | 12.5 yrs |
Modelled, not quoted. Production is system size × 4.4 peak sun hours × 365 days × 0.8 for inverter, wiring, soiling and heat losses. Savings value that production at 16.5¢ per kWh and hold the rate flat for year one. Panel count assumes 400 W modules. Your roof, your shade and your usage move all of it.
No federal credit is in these numbers. The 30% homeowner credit (IRC Sec. 25D) ended for systems placed in service after December 31, 2025. Net cost above is gross cost minus whatever state or local money is still open — nothing else. If a quote knocks 30% off and calls it a federal credit, ask which statute they are citing.
Permits and approvals in Wilmington
Two approvals, two bodies. The Wilmington building department issues the electrical and structural permit. Delmarva Power issues permission to operate once the work is inspected and, where required, the meter is swapped. Nothing generates a single legal kWh until the second one lands, and the two queues do not move at the same speed.
Permit fees and turnaround vary by jurisdiction and we do not track them, so we are not going to print a number we cannot source. Make the installer put the permit cost and the expected wait for both approvals in the written quote instead of leaving them as a line you discover afterwards.
Incentives and the full state picture: solar panels in Delaware.
Questions from Wilmington
How much do solar panels cost in Wilmington?
A 8 kW system in Wilmington models at $23,200 installed and $20,700 net, at the Delaware average of $2.90 per watt. There is no federal homeowner credit in that — the 30% credit ended for property placed in service after December 31, 2025. Quotes inside one city still vary by several thousand dollars depending on roof pitch, panel choice and whether the main service panel needs upgrading.
Who is the electric utility in Wilmington?
Delmarva Power serves most of Wilmington. It is investor-owned utility — regulated by the state public utility commission, so the statewide net metering or net billing rule below is the one that applies to you, and any change to it goes through a public docket you can read. That matters more than it sounds: your utility, not your installer and not the state, sets what an exported kWh is worth and how long permission to operate takes. Service territories cut across city limits, so check the name at the top of your own bill.
Does Delmarva Power pay for solar you send back to the grid?
Delmarva Power is an investor-owned utility, so the Delaware rule applies to it: Delaware has full retail net metering with annual true-up, and homeowners can also sell SRECs into the state's compliance market. Ask for the specific rider name and the credit rate in writing before you sign — it is a tariff, and tariffs get refiled.
Is solar still worth it in Wilmington now the federal tax credit is gone?
On these numbers it pays back in about 12.2 years with no federal credit at all — $20,700 net against roughly $1,696 of electricity offset a year. Delaware still runs Delmarva Green Energy Program, worth roughly $2,500 here, and that is already in the figure. What decides it in Wilmington is the 16.5¢ per kWh you pay now and what Delmarva Power credits your exports at, not the subsidy that ended.
Does shade in Wilmington kill the numbers?
Heavy shade does, and no amount of panel technology fixes it. Partial afternoon shade usually costs a modest percentage of production, which the modelling above does not attempt to guess at. If mature trees cover the south face of your roof for most of the day, the honest answer is not to bother.
Where to look next
Incentives, electricity rates, net metering rules and the full Delaware picture live on the state page: solar panels in Delaware.