PLUGWATTS / MARYLAND GUIDE

Maryland plug-in solar: what to check before you buy

By PlugWatts editorial · Reviewed September 14, 2026 · 9 minute read

Maryland allows one qualifying plug-in solar system per electric meter for residential use, with output up to 1,200 watts. The device must have certification from UL or an equivalent nationally recognized testing laboratory. You must notify your utility before installation. For qualifying systems, the utility cannot require advance approval or charge a fee related to feeding electricity back. Maryland law, § 7-321

That gives households a way to consider small solar without a full rooftop project. Whether it is a good purchase comes down to the equipment, the space available, and how much of its electricity your home can use.

Our advice: Before choosing a kit, establish three things: where it can go, whether its certification matches what you are buying, and how your utility meter handles extra electricity. Those answers can change both the equipment you need and the value you get.

Sources reviewed September 14, 2026. This guide helps organize a purchase decision; it does not approve an installation.

Maryland's rules at a glance

Source: § 7-321, subsections A–E. The separate 391 W provision is explained below.

First, decide what you want the system to do

If your goal is a lower electricity bill, focus on usable energy and total cost. If your goal is to keep a refrigerator running during an outage, investigate the exact equipment's backup capability and connection requirements separately. A plug-in solar label alone does not establish either result.

Start with the space you have. Note when it receives direct sun, what shades it, where the panels would sit, and where the cable would run. In an apartment or shared building, identify which unit or account serves the proposed outlet. An outlet near your balcony may not be on your own meter.

Before spending money, ask whoever controls the proposed location which permissions apply. For a rental or condo, that may involve the lease, association documents, or a property manager. Record any required permission and agree on removal and restoration. If there is a dispute about your rights, seek advice on the applicable law rather than assuming either the solar rule or a property restriction settles it.

These are practical screening steps. They do not replace an assessment of the mounting or electrical work. SMECO advises customers to consult a qualified electrician when unsure whether their home's electrical system is compatible. SMECO registration guidance

What the 391-watt exception actually changes

At 391 W or less, Maryland exempts a system from product-listing provisions that would require changes to the building's premises, wiring, or electrical panels. Certification remains part of the qualifying-device definition. § 7-321, subsections A and F

For a buyer, the useful question is: Which installation conditions apply to this exact system at this output? Ask the seller to point to the relevant instructions and certification record. If those documents appear to require alterations, have the question resolved for your configuration before ordering.

Do not read 391 W as a guarantee that an existing outlet is suitable. Likewise, being under the 1,200 W ceiling does not establish that a larger kit can use your proposed circuit unchanged.

Make sure you are comparing the right numbers. A solar panel's advertised wattage and the system's output to the home describe different parts of the equipment. Ask for the maximum output of the configuration being sold, including any output limit, rather than relying on the bundle name.

Check the product evidence before choosing a brand

We would ask the seller for:

• The exact models of the panels, inverter, connection hardware, and any controls included in the kit.
• The certifying laboratory, certificate or listing number, and a link to its product record.
• Documentation showing which models and configurations the record covers.
• Instructions for the U.S. version, including mounting and connection requirements.
• The warranty, return conditions, and a complete list of hardware you must buy separately.

Match those records to what will arrive in the box. A certificate for a different inverter, or a familiar logo on one component, leaves a question about the proposed kit. Ask the certifier or manufacturer to resolve it.

Missing evidence means unverified. It does not, by itself, prove a product lacks certification. Our buying recommendation is to wait until the necessary evidence is available, rather than treat a sales claim as the answer.

This guide does not evaluate or recommend a particular kit. For the broader equipment and site questions, read our plug-in solar safety guide.

Ask about your meter before estimating savings

The Maryland PSC warns that some meters may ignore exported energy or mistakenly add it to measured consumption. It directs customers to their utility for the answer. PSC meter guidance

Ask: “For the meter at my address, how would a portable solar system's exported electricity appear on my bill?” Request a written answer or keep a dated call record. If the answer is unclear, leave export value out of your savings estimate and resolve the potential billing risk before installation.

A simple example: production is not the same as savings

Suppose a system produces a steady 300 W for one hour. That is 0.3 kilowatt-hours (kWh) of energy. If your home uses only 200 W throughout that hour, it uses 0.2 kWh of the solar output and exports the remaining 0.1 kWh, assuming no storage or export limit.

At an illustrative avoided electricity cost of 20 cents per kWh, the energy used at home saves 4 cents for that hour. If exported energy receives no credit, it adds nothing to that saving.

Now suppose your annual estimate is 500 kWh of solar energy used at home. At the same illustrative rate, that saves $100 a year. A total project cost of $1,000 would imply a ten-year simple payback before maintenance, financing, degradation, or changes in electricity prices.

These are arithmetic examples, not Maryland production forecasts, current tariff claims, or product prices. Use your own avoidable per-kWh charges; fixed monthly charges generally remain outside this calculation. Include any mounting, electrical work, delivery, and required hardware in the project cost.

Our buying test is straightforward: does a conservative estimate justify the total cost over the time you expect to use the equipment? A larger system deserves consideration only if the extra usable energy justifies the extra expense.

Notify the utility before installation

Find the serving utility on your bill, then use its current notification route. Identify the process before buying so you know which equipment information to collect. Keep the submission and any response with your project documents.

The following starting points are listed by the Maryland PSC as of the review date. This is a directory of published routes, not a claim that PlugWatts has tested each submission process.

If a link changes or the instructions do not address your situation, return to the PSC directory and ask the utility for its current portable-solar process.

Your Maryland buying checklist

This worksheet separates purchasing decisions from the steps needed before installation. The evidence items are PlugWatts recommendations for keeping a useful record, not a claim that every document is legally mandatory.

Where does your proposal stand?

• Ready for a closer assessment: The basic state conditions appear to fit and you have the product evidence. Check the location, costs, and installation requirements before committing.
• Not enough information yet: A certificate, meter answer, permission, or site assessment is missing. Resolve that item; absence of evidence is not a final legal determination.
• Outside these portable-solar rules: The proposal exceeds the output limit, adds a second system to the meter, or is for non-residential use. Ask about a different solar arrangement.

Get a checklist for your answers

The PlugWatts Check asks eight questions about your state, property, sunlight, proposed output, and the issues you have already verified. It returns a conditional result with next steps you can print. It does not look up your address or independently verify a product, meter, or installation.

Check my plug-in solar fit

Read next: how plug-in solar works, state rules and coverage, and safety questions.

Sources and corrections

The legal summary is based on Maryland's 2026 Chapter 353, § 7-321 and the PSC's balcony-solar guidance. Utility-specific electrical guidance is linked to SMECO. Sources were consulted September 14, 2026.

The worksheets and arithmetic examples are PlugWatts editorial tools. This article reports no hands-on product testing. If a source changes or a statement needs correction, contact PlugWatts.