The rules in the US
There is no federal rule. Utah was first (2025): kits up to 1200 W into a 120 V outlet, with no interconnection agreement. Other states have passed or are passing similar laws.
Check your state and your utility before you buy. Power you feed into the grid is not paid for.
The federal 25D tax credit ended for systems installed after 31 December 2025.
How much does a balcony solar kit produce?
It depends on three things: where you live, which way the panels face and how steep they hang. We take the yield for your city from PVGIS, the European Commission’s solar database, for panels facing south at 30° and for panels hanging straight on a railing facing south, east or west.
A railing mount makes less than a tilted one, most of all in summer when the sun is high, but it is how most balcony kits are fitted. East and west make less again, but spread over the morning or the evening, when many homes use more.
How much does it save?
Only what your home uses as the kit makes it saves money: at your full tariff. What it makes while nobody needs power goes to the grid, usually unpaid. Consumer guides put the share a home uses at about 30% when nobody is in during the day, about half for a home that is, and 60–80% with a small battery.
So the payback is the kit’s price over the yearly saving. A fridge, a router and a home office during the day raise the share; a battery raises it most, but also the price.
How we calculate
Yearly output = the panels’ power × the yield per kWp at your place and mount (PVGIS 5.3, 14% system losses). Panels above the inverter’s limit count half: they help in the morning, the evening and under cloud, but the inverter cuts their midday peak.
Saving = output × the share your home uses × your tariff. The tariff starts at your country’s average; set your own. Panels age by about half a percent a year, which we leave out.
Which way should the panels face?
| City | tilted 30°, facing south | on the railing, facing south | on the railing, facing east | on the railing, facing west |
|---|---|---|---|---|
| New York | 1,382 | 939 | 687 | 560 |
| Chicago | 1,460 | 977 | 709 | 669 |
| Los Angeles | 1,781 | 1,066 | 858 | 852 |
| Phoenix | 1,826 | 1,109 | 894 | 835 |
| Salt Lake City | 1,797 | 1,211 | 863 | 853 |
kWh a year per 1,000 Wp of panels (PVGIS 5.3, 14% losses).
Questions
Is a balcony solar kit worth it?
Usually yes, if the panels get sun for most of the day and someone uses power while they make it: kits cost a few hundred and last 20 years or more. A shaded or north-facing balcony is the exception.
How much does an 800 W balcony kit produce?
With two panels, 850–1,640 kWh a year in our cities, depending on the city and the mount. The calculator shows yours.
Can I plug it into a normal socket?
In states that allow it, yes: a kit with a certified microinverter into a 120 V outlet. Check your state first.
Do I get paid for the power I feed in?
Usually not for a plug-in kit: the meter may count it, but it is not paid. That is why the calculator counts only what your home uses.
More free tools
Sources: PVGIS 5.3, European Commission Joint Research Centre · Utah HB 340 (2025): portable solar generation devices · US plug-in kits of about 800 W at $699–945 (The Gadgeteer, May 2026) · US EIA, Electric Power Monthly: average residential price, August 2026 · Updated 12 November 2026