Plug-in solar
Plug-In Solar Panels for Home: Sizes, Setups and Limits
Plug-in solar panels for home range from about 180 W to the 1,200 W cap most state laws set. Sizes, setups, circuit limits and what each one produces.
Key facts
- US plug-in kits range from about 180 W to 1,200 W of inverter output; most state laws cap a device at 1,200 W.
- At an average US yield of about 1.4 kWh per watt per year, a tilted 800 W kit produces roughly 1,100 kWh, about a tenth of the 10,791 kWh an average US home bought in 2022.
- A 1,200 W inverter puts 10 amps on a 120 V circuit; a 15 A circuit is rated for 1,440 W of continuous load.
- Maryland and Virginia exempt devices of 391 W or less from listing rules that would require wiring changes; Maine allows up to 420 W on an existing outlet.
- Under the state plug-in laws, exported surplus earns no credit, so the best size matches your home's daytime base load.
Plug-in solar panels for home are small grid-tied systems: one to four panels, a microinverter and a cord to a standard 120 V outlet. US kits range from about 180 W to 1,200 W, the cap most state laws set. A tilted 800 W kit produces roughly 1,100 kWh a year, about a tenth of what a typical home buys. Size it to daytime use; exported surplus earns nothing.
What a plug-in solar system for home includes
Every kit, whatever its size, has the same parts. What differs is how many panels feed the inverter and whether a battery sits between them and the outlet.
| Part | What it does | What to check |
|---|---|---|
| Panels | Convert sunlight into DC electricity | rated watts, dimensions and weight for your mount |
| Microinverter | Converts DC to 120 V AC in step with the grid; shuts off when the grid fails | maximum AC output, listing by a recognized lab |
| AC cable and plug | Connects the inverter to an outlet | length, outdoor rating; no extension cords |
| Mount | Holds the panels on a railing, wall, ground or flat roof | wind rating, no drilling for rentals |
| Battery unit (optional) | Stores midday surplus and releases it later | usable capacity, output limit, backup outlet |
| Monitoring (optional) | App or display of production | not required, useful for sizing |
The inverter is the part that decides legality. State laws cap the device’s output, usually at 1,200 W, and require certification by a nationally recognized testing laboratory. UL 3700 is the new safety standard written for plug-in systems; UL Solutions launched certification to it in January 2026, and the first compliant microinverter was announced in July 2026. Our guide to plug-in solar inverters explains listings and ratings, and what plug-in solar is covers the basics.
Sizes: from 180 W to 1,200 W
The table uses an average US yield of about 1.4 kWh per watt of panels per year for a tilted, south-facing, unshaded installation, from the PVWatts range (National Laboratory of the Rockies, formerly NREL), and compares it with the 10,791 kWh an average US residential customer bought in 2022 according to EIA.
| Kit size (inverter output) | Typical panels | Yearly output, tilted | Share of an average home’s use | Fits a daytime base load of |
|---|---|---|---|---|
| 180 to 200 W | 1 small panel | about 250 to 280 kWh | about 2 to 3% | almost any home |
| 400 W | 1 to 2 panels | about 560 kWh | about 5% | 150 W and up |
| 800 W | 2 panels | about 1,120 kWh | about 10% | 300 W and up |
| 1,200 W | 3 to 4 panels | about 1,680 kWh | about 16% | 500 W and up |
Yields range from about 1.2 kWh per watt in the Pacific Northwest to about 1.8 in the desert Southwest. A panel hung vertically on a south-facing railing loses roughly a quarter to a third of the tilted figure. Our cost and savings guide has the regional table.
Panel capacity may be somewhat higher than inverter output; the inverter simply caps the peak. That raises production in the morning, evening and winter without exceeding the legal limit, which is set on output.
The limits that decide your size
Three limits stack on top of each other, and the lowest one wins.
The state cap. Utah, Maine, Maryland, Virginia and California cap a device at 1,200 W; Maryland and Virginia apply it per meter or dwelling unit. Colorado’s law allows up to 1,920 W of output, one system per address. In states without a plug-in law, there is no plug-in category at all; see plug-in solar laws by state.
The outlet threshold. Some laws treat small devices differently. Maryland and Virginia exempt devices of 391 W or less at the outlet from listing rules that would require changes to wiring or panels. Maine allows up to 420 W per address on an existing outlet and requires a licensed electrician and a dedicated circuit with a single outlet above that.
The circuit. A 1,200 W inverter puts 10 amps on a 120 V circuit. A common 15 A household circuit is rated for 1,800 W, or 1,440 W for continuous loads under the usual 80 percent rule. The breaker in your panel only sees current coming from the grid, not the current your kit adds further down the circuit, so a large kit on a shared circuit can let the wiring carry more than the breaker protects against. That is why a dedicated circuit is the safer choice for anything above a few hundred watts. Our guide to 1,200 W plug-in solar goes through the arithmetic.
Setups: balcony, yard, wall or roof
Where the panels go matters as much as how many you buy.
| Setup | Yield compared with tilted south | Good for | Watch out for |
|---|---|---|---|
| Ground stand in the yard, tilted south | 100% | houses, ground-floor units | shade from fences and trees, mowing |
| Flat roof of a garage or shed, tilted | about 100% | houses with outbuildings | ballast or anchoring against wind, roof access |
| Balcony railing, vertical, facing south | about 65 to 75% | apartments | shade from the balcony above, wind on upper floors |
| Wall or fence, vertical, facing south | about 65 to 75% | houses without yard space | mounting into masonry, HOA rules |
| East- or west-facing vertical | about 50% | when nothing else is available | low midday output, better morning or evening |
A south-facing tilt near your latitude gives the most energy over a year. East-west setups produce less in total but spread it across the day, which can match household use better. The PVWatts calculator accepts any tilt and azimuth and estimates the yield for your address in a minute.
Matching the kit to your home
The figure that matters is your daytime base load: the power your home draws continuously while the sun is up. In a typical home that is the refrigerator, freezer, router, standby electronics, ventilation and anything left running, often 150 to 400 W, plus air conditioning or a home office during the day.
Many utilities show hourly use in their app or online account if you have a smart meter. Look at a sunny weekday and read the consumption between 10 a.m. and 3 p.m. If it stays around 300 W, an 800 W kit will export part of its midday peak; a 400 W kit will be used almost entirely. If it stays above 600 W because the air conditioning runs, a 1,200 W kit makes sense.
| Household pattern | Daytime base load | Sensible kit | Share used at home, roughly |
|---|---|---|---|
| Apartment, empty during the day | 100 to 200 W | 200 to 400 W | 80 to 90% |
| Apartment or small house, someone home | 200 to 400 W | 400 to 800 W | 70 to 80% |
| House with air conditioning or home office | 400 to 800 W | 800 to 1,200 W | 60 to 75% |
With or without a battery
A battery unit sits between the panels and the outlet, stores midday surplus and releases it in the evening, still within the device’s output cap. It raises the share of solar used at home to 90 percent or more. Some units also have a backup outlet that keeps a few devices running during an outage, which the grid-tied inverter alone cannot.
The battery is usually the most expensive part of the kit. It pays mainly when nobody is home during the day, when the kit is large relative to the base load, or when backup matters to you. Maine’s law covers plug-in batteries explicitly; elsewhere, check that the battery unit is part of the certified device.
Plug-in solar compared with rooftop solar
| Plug-in kit | Rooftop system | |
|---|---|---|
| Typical size | 180 to 1,200 W | 5 to 10 kW |
| Installation | do it yourself, plug into an outlet | licensed installer, hardwired |
| Permit and utility approval | not required for compliant devices in states with a plug-in law | required |
| Credit for exports | none under the plug-in laws | net metering or export rate in most states |
| Share of an average home’s use | about 2 to 16% | most or all |
| Moves with you | yes | no |
Plug-in solar is not a cheaper rooftop system. It is a small appliance that trims your bill, suited to renters, apartments and homeowners who want to start small.
Choosing and installing a kit
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Check the rules. State law, utility notice, lease or HOA. Our guides on telling your utility and plug-in solar for renters cover the details.
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Measure your daytime load. Use hourly smart meter data or the readings of a plug-in energy monitor on a sunny weekday.
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Pick the location. South, unshaded, close to a grounded outdoor outlet. Measure the space and check the railing or ground for strength.
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Choose a certified kit. Inverter output within your state’s cap and your circuit’s capacity, certification of the device by a recognized laboratory, 120 V and 60 Hz.
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Mount the panels. Use rated brackets, tighten them as specified and secure the cable against wind and foot traffic.
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Plug in and check. Connect the panels to the inverter first, then the inverter to the outlet. Watch the first sunny day’s output in the app or on an energy monitor.
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Notify where required. Send the utility notice your state requires and tell your insurer.
Mistakes to avoid
- Extension cords and power strips. They are not designed for a power source and can overheat.
- Two kits on one circuit. Their currents add up on wiring the breaker does not see.
- Oversizing. Surplus earns nothing; a kit that exports half its output pays back slowly.
- European kits. A 230 V, 50 Hz inverter with a European plug does not work on the US grid and has no US certification.
- Shade. Panels are wired in strings of cells, so shade on a small part of a panel can cut a large share of its output.
- Ignoring wind. Panels act as sails. Use brackets rated for the panel’s area.
Next steps
Frequently asked questions
What size plug-in solar system do I need for my home?
Size it to the power your home draws during the day, not to your total bill. A home with a daytime base load of 200 to 400 W uses most of a 400 to 800 W kit; a larger home with air conditioning or someone working from home can absorb 1,200 W. Exported surplus earns nothing under the plug-in laws.
Can plug-in solar power a whole house?
No. The largest legal kits deliver 1,200 W at most, while an average US home bought 10,791 kWh in 2022 according to EIA. A tilted 1,200 W kit produces about 1,700 kWh a year, roughly a sixth of that, and nothing during a power outage.
How many plug-in solar panels can I connect to one outlet?
As many as the inverter rating allows, which most laws cap at 1,200 W per device or dwelling. Maryland allows one system per meter. Maine requires a dedicated circuit for each system above 420 W, and you should never put two kits on the same circuit.
Do plug-in solar panels work during a power outage?
Not on their own. A grid-tied microinverter must shut off when the grid fails. Kits with a battery unit that has its own backup outlet can supply a few devices during an outage, and a portable power station charged by panels works independently of the grid.
Is it better to put plug-in panels on a balcony or in the yard?
A ground stand in the yard, tilted toward the south, produces about a third more than the same panel hung vertically on a balcony railing. The balcony is the only option in many apartments. Shade from the balcony above or nearby trees costs more yield than orientation.
What is the difference between plug-in solar and rooftop solar?
Scale and paperwork. Rooftop systems are typically 5 to 10 kW, hardwired by an installer, permitted and usually net-metered. Plug-in kits stay at or below 1,200 W, plug into an outlet, and in states with a plug-in law need no interconnection agreement, but their exports earn nothing.
Do I need a battery with plug-in solar?
Not for savings in most homes. A battery raises the share of solar you use yourself, which matters when nobody is home during the day or the kit is large. It adds several hundred dollars or more to the price, so it pays mainly when you also want backup for a few devices.
Sources
- Balcony Solar
- Va. Code § 56-596.8: Small portable solar generation devices; exempt from interconnection
- 35-A MRSA § 3475: Plug-in photovoltaic and plug-in battery systems
- How much electricity does an American home use?
- PVWatts Calculator
- UL Solutions debuts testing and certification framework for safer plug-in solar
- Hoymiles introduces HiFlow Pro, the first UL 3700-compliant plug-in microinverter in the US
- Colorado Session Laws 2026, Chapter 127 (HB26-1007), signed act
- Plug-in solar legislation tracker
This guide is general information, not legal, tax or electrical advice. Your utility, state and local code have the final say.