Quick answer: an 800W plug-in solar kit in average US sun makes about 1,100kWh a year facing south with no shade, or about 900kWh facing east or west. At 18¢ per kWh that saves roughly $145–$185 a year, so a $1,000 kit pays for itself in about 5½ to 7 years. Shade, an east or west aim, or a vertical railing mount all cut that. Run your own numbers below.
Balcony solar savings
How the estimate works
Yearly kWh = panel watts ÷ 1,000 × peak sun hours × 365 × placement factor × 0.86. The 0.86 covers inverter, wiring, heat and dust losses. The placement factor reflects the fact that panels flat against a railing or facing east or west catch less sun than a tilted, south-facing panel. Savings count only the share you use as it is made, since most plug-in kits don't get paid for power sent back to the grid.
Is it legal where you live? Plug-in solar that feeds a wall outlet is common in Germany, where many apartment balconies have it. In the US it is only starting to be allowed: Utah was first in 2025, and other states have bills pending. If yours hasn't acted, the safe route is the kind of kit in our plug-in solar gear guide: panels charge a power station, and the station powers your devices. The same math applies to the energy those panels harvest.
Frequently Asked Questions
How much electricity does an 800W balcony solar system produce?
About 700 to 1,200kWh a year in the US, depending on sun and placement. A south-facing, unshaded 800W kit in average US sun (4.5 peak hours) makes roughly 1,100kWh; mounted vertically on a railing, closer to 800kWh.
How long does balcony solar take to pay for itself?
Usually 5 to 10 years. An 800W kit that costs $1,000, makes 900kWh a year and has 90% of it used at home saves about $145 a year at 18 cents per kWh, a payback of roughly 7 years. Higher electricity rates shorten it.
Is plug-in balcony solar legal in the US?
It is only starting to be. Utah legalized small plug-in solar systems in 2025 and several other states have proposed similar laws. Elsewhere, check with your state and utility, or use panels that charge a portable power station instead of feeding an outlet.
Do I need a battery with balcony solar?
Not to save money on a grid-tied plug-in kit, but without one you only benefit from power used as it is produced. A battery or power station stores midday output for the evening and raises the share you actually use.
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