Plug-In Solar in Delaware: Net Metering, No Sales Tax, Small State

Delaware rarely comes up in solar conversations — it's the second-smallest state by area and doesn't have the headline-grabbing policy fights of California or the hurricane urgency of Florida. But for a small plug-in solar setup, Delaware quietly offers two of the best fundamentals in the country: genuine 1:1 net metering and no state sales tax on the equipment you buy to get there.

Why Delaware's numbers work in your favor

Delaware's Renewable Portfolio Standard requires utilities to source a growing share of power from renewables, and the state backed that up with a net metering law that — unlike California's NEM 3.0 — still credits exported solar at the full retail rate, not a discounted wholesale rate. For a small 400-800W plug-in kit, that distinction matters more than almost anything else in the economics.

• Average residential rate: ~15-17¢/kWh (close to the national average, a bit above neighboring Pennsylvania)
• Net metering: True 1:1 retail credit, available to systems up to 25kW for residential customers
• Sales tax: Delaware has no state sales tax at all — on solar equipment or anything else
• Primary utility: Delmarva Power, an Exelon subsidiary covering most of the state

That last point is easy to overlook. A buyer in a state with 6-8% sales tax pays that on top of list price for a $600-900 kit. In Delaware, the sticker price is the price.

The interconnection question

Here's where Delaware gets more interesting for plug-in kits specifically. Formal net metering interconnection in Delaware requires an application to Delmarva Power, inspection, and a bidirectional meter — the same paperwork-heavy process every state with net metering uses for rooftop systems. Most of that process assumes a licensed-installer rooftop array, not an 800W kit someone plugs into a garage outlet.

In practice, most Delaware plug-in solar buyers fall into the same grey zone documented across the rest of the US: a small kit (under 800W) with a UL 1741-listed microinverter connected behind a standard outlet, without going through full net metering interconnection. You're not "selling back" surplus formally — you're simply reducing your own draw from the grid while the panel is producing, which needs no utility paperwork at all. If you want the full net metering credit on exported power, you need the formal Delmarva Power application, which usually only makes financial sense once you're installing a larger, roof-mounted system.

For the baseline legal picture across all 50 states, start with our state-by-state legality guide, and read NEC Article 705 if you want the specific code section utilities and inspectors reference.

What actually pays off in Delaware

Delaware's flat, humid-summer climate is reasonably solar-friendly — not Arizona-level irradiance, but comparable to Pennsylvania or New Jersey, both of which have mature small-solar markets next door.

• An 800W kit generating through self-consumption during the day will offset roughly 500-700 kWh/year depending on orientation and shading, worth roughly $85-120/year at Delaware's average rate.
• Payback on a $700-900 kit lands in the 6-9 year range on self-consumption alone — not instant, but helped meaningfully by paying zero sales tax upfront, which most other states' buyers don't get.
• HOAs are common in Delaware's newer developments (particularly around Middletown and Dover), and many apply the same restrictions on visible equipment covered in our HOA rules guide — check your covenant before mounting anything visible from the street.

Who should actually consider this

Delaware's case is strongest for homeowners who want a low-friction, low-cost entry into solar without committing to a full installer-quoted rooftop system. If you're renting or in a townhouse with limited roof access, a plug-in kit on a patio or balcony captures most of the self-consumption benefit without any interconnection paperwork at all — see our apartment and renter guide for layout ideas that work in tight spaces.

If you're a homeowner seriously considering a larger system and want the full retail-rate net metering credit, it's worth getting quotes from installers who already handle the Delmarva Power interconnection paperwork routinely — that process is the same whether you add one panel or twelve, so the fixed cost is better amortized over a bigger system.

Nearby states for comparison

If you're close to a state line, it's worth checking how Delaware compares: Pennsylvania and New Jersey both border Delaware and have their own net metering quirks, while Maryland sits just across the Delmarva Peninsula with a similar utility landscape. None of the four states' rules are identical, so don't assume a neighbor's setup applies to you.

For the federal incentive layer that applies regardless of which of these states you're in, see our federal tax credit guide — small plug-in kits don't always qualify the way full installed systems do, so check the thresholds before counting on it in your payback math.

Does Delaware have a state sales tax on solar equipment?

No. Delaware has no state sales tax at all, on solar equipment or any other retail purchase, which gives plug-in solar buyers a small but real cost advantage over states with 6-8% sales tax.

Do I need to notify Delmarva Power to run a small plug-in solar kit?

Formal net metering interconnection paperwork is required if you want retail-rate credit for exported power, but most small kits under 800W are used purely for self-consumption without going through that process, similar to the grey-zone approach used across most other US states.

How does Delaware's net metering compare to California's?

Delaware offers true 1:1 retail-rate net metering, while California's NEM 3.0 pays a much lower wholesale-linked rate for exports. For a self-consumption-focused plug-in kit the difference matters less, but it makes a larger grid-tied system far more favorable in Delaware than in California today.