Plug in solar: how much it really produces and what is allowed

Vertical on the railing costs about a third

Fraunhofer ISE puts the loss of a vertical south facing panel at about 29 percent compared with the best tilt. In winter the vertical panel can even win, because it faces the low sun head on. East and west balconies produce roughly 30 percent less than south.

Calculate the yield for your balcony

Shade matters more than you think

In a Stiftung Warentest test of eight systems, a quarter of the panel in shade left even the best system with little more than half its output. A plant pot or a balcony divider can cost more than a poor orientation.

The 800 W rule and registration

Most countries now allow plug-in systems with an inverter of up to 800 W, and an EU recommendation of April 2026 asks all member states to remove obstacles. Switzerland still limits them to 600 W. How you register differs a lot: a register in Germany, the grid operator in Austria, Switzerland and the UK, the Enedis agreement in France and regional rules in Belgium.

Rules by country, with check date

What a balcony system produces in seven cities

We ran the same calculation as our calculator for seven cities, with PVGIS data from the European Commission: 800 Wp, 600 Wp in Switzerland, no shade. The table confirms the rule of thumb above: vertical on the railing gives roughly 30 percent less than a 35 degree tilt, and a west facing railing about 30 percent less again. Lyon in the south leads, Zurich trails because of the smaller Swiss limit.

Calculate the yield for your own balcony