What a Balcony Panel Really Earns on Your Berlin Wall
An 800 watt kit is sold on one number, and what reaches your bill depends on which wall it hangs on, how it hangs and how much your flat is drawing while the sun is up. Turn the dial to your real balcony direction and the whole Berlin year redraws, split into the part you use and the part you give away for nothing.
Yields are modelled for Berlin Mitte with PVGIS, the European Commission JRC solar database. Every month comes from the 2005 to 2020 long-run average for that orientation and tilt. How much of each hour a flat actually swallows is measured on the 2018 to 2020 hourly series and applied month by month, with the 800 W AC inverter limit clipped hour by hour, which is why the larger module sizes add far less than they look like they should. The sky is modelled clean: a courtyard balcony with a building opposite will sit well under these numbers. The euro figures use 37.93 cents per kilowatt hour, the Vattenfall Berlin basic tariff since 1 April 2026.
Turn the dial to the direction your balcony faces. The compass shows what every direction keeps over a year at your chosen mounting, and the twelve bars show the month by month output, with the dark part being what your flat uses at the moment it is made. Everything above that line leaves at the unpaid standard feed-in, which is why the household draw moves the answer more than the compass does.
Only what you use at that moment is money
The standard arrangement for a plug-in solar device is unentgeltliche Abnahme: anything you send out of the flat is taken for free. So the figure that decides the payback is not what the panel makes, it is what your flat is drawing while it makes it. A flat with a fridge, a router and some standby sits around 130 watts, and on a south-facing railing it keeps roughly half of what an 800 watt peak kit produces.
More panel is usually the wrong upgrade
The legal ceiling is 2,000 watt peak of module behind an 800 watt inverter, and on a south railing that lifts annual production from 595 kWh to about 1,318. A 130 watt flat keeps 306 of the first and 379 of the second, so several hundred euro of extra glass buys roughly 28 euro a year. If somebody is home during the day the picture reverses, which is the one question worth answering before you order.
Angle matters more than the compass
Laying the panels back at 30 degrees on a north balcony beats bolting them flat to a south railing in kept kilowatt hours. A vertical panel also beats a tilted one in November, December and January, because it faces the low winter sun head on and that is the half of the year when you are at home with the lights on.
The Berlin rules in one paragraph
No building permit is needed under the Bauordnung Berlin, though a listed building needs the district Denkmalbehoerde. Since October 2024 a landlord or owners association needs a concrete reason to refuse. You register the device in the Marktstammdatenregister within a month and tell the grid operator nothing. A certified device may use a normal Schuko socket up to 960 watt peak of module, and above that an electrician fits a proper feed-in socket.