The rules in Europe
Most of the EU allows plug-in kits up to 800 W at the inverter; Germany also allows up to 2,000 Wp of panels and needs only a registration. Switzerland stops at 600 W.
Power fed into the grid is usually not paid for: what counts is what your home uses as it is made.
Ask your landlord or owners’ association first; in Germany they can refuse only for good reason.
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 |
|---|---|---|---|---|
| Berlin | 1,041 | 758 | 531 | 515 |
| Munich | 1,130 | 812 | 557 | 556 |
| Vienna | 1,167 | 822 | 562 | 571 |
| Zurich | 1,144 | 801 | 545 | 560 |
| Paris | 1,125 | 799 | 571 | 533 |
| Lyon | 1,281 | 884 | 622 | 615 |
| Marseille | 1,611 | 1,108 | 747 | 759 |
| Milan | 1,354 | 956 | 622 | 658 |
| Rome | 1,492 | 1,000 | 724 | 680 |
| Naples | 1,529 | 999 | 718 | 721 |
| Madrid | 1,610 | 1,079 | 795 | 750 |
| Barcelona | 1,550 | 1,044 | 657 | 745 |
| Seville | 1,667 | 1,069 | 795 | 793 |
| London | 1,010 | 743 | 521 | 499 |
| Manchester | 880 | 646 | 458 | 444 |
| Glasgow | 845 | 633 | 429 | 435 |
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, 540–1,420 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 most of Europe and, since August 2026, in Great Britain, yes, within the power limit and with a certified kit. Use a socket of its own, never an extension lead or a multi-plug.
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 · Verbraucherzentrale: Neue Norm für Balkonkraftwerke (2025) · UFC-Que Choisir: 22 kits compared, May 2026 (€299–999, average €552) · Eurostat: EU average household electricity price, first half of 2026 · Updated 12 November 2026