Balcony solar calculator

Per household: an inverter up to 800 W AC output and up to 2,000 Wp of module power. On a regular Schuko socket, the 960 Wp limit of DIN VDE V 0126-95 additionally applies since December 2025 — more module power requires a dedicated connector (e.g. Wieland). Registration is now only in the Marktstammdatenregister (within 1 month of commissioning); the separate grid-operator notification is gone. The calculator checks all of this as a traffic-light panel before computing.

In Berlin the vertical south facade delivers about 730 kWh per kWp per year — computed from PVGIS hourly data, not estimated. Two 445 Wp modules (890 Wp) reach about 650 kWh. Tilting to 45° would add a computed third or so (+37%, still +32% at 60°); in return the vertical surface performs relatively better in winter, catching the low sun.

Because their power is small compared with the household base load: almost all generation is used directly and valued at the full electricity price — 82% computed self-consumption in the reference case (890 Wp, 3,000 kWh household). At 31.1 ct/kWh and €500 system cost that is about €166 saved per year and roughly a 3-year payback. The rest is exported unpaid — the calculator states this openly.

It does not assume it, it computes it: for all 8,760 hours of the year, generation is matched against a disclosed household profile of your type (working, home office, retired, family, shift) — the same HTW-validated model as in the self-consumption calculator. A retired household uses noticeably more directly than a commuter household.

Hardly, for typical setups: 890 Wp vertical on the railing practically never reaches the 800 W limit (loss below 0.5%). The limit only bites with large module power at shallow tilt — 2,000 Wp at 35° lose a computed 330 kWh, about 16%, in the Berlin reference year. The calculator quantifies the hourly curtailed energy for your configuration.

Little, but not nothing: in the Berlin reference case (890 Wp vertical south) December through February deliver about 100 kWh together — roughly 15% of the annual yield, averaging 0.9 kWh per day in December versus 1.9 in July. Vertical railing mounting is the most winter-friendly geometry: it catches the low winter sun best and snow cannot settle — a 15% winter share at 90° versus 11% at 35° tilt. All computed hourly from the TMY data of your location.

Yes, with a computed discount: vertical on a Berlin railing, the east side delivers about 25% and the west side about 31% less than south (486 and 450 instead of 650 kWh at 890 Wp). Savings drop less than yield, because morning and evening generation match the household profile better — on the west side a computed 97% is used directly. The calculator computes your orientation hourly instead of applying a flat formula.

Allowed: 2,000 Wp of module power is the ceiling for plug-in solar devices; above 960 Wp, DIN VDE V 0126-95 requires a dedicated connector instead of Schuko, and the inverter stays at 800 W. Yield: 2,000 Wp at 35° tilt deliver a computed 1,678 kWh per year in Berlin — 4.6 kWh per day on average — of which the 800 W limit clips 330 kWh (16%). In a 3,000 kWh household only 56% is self-consumed; 747 kWh are exported unpaid. Going big pays off mainly with high consumption — or a battery.

Legally this relaxed in 2026: VDE-AR-N 4105:2026-03 brings AC-coupled batteries on balcony systems into the simplified procedure — laypersons may register them, and the combined 800 W limit at the grid connection still applies. The product standard DIN VDE V 0126-95 does not yet cover devices with storage, which is why the calculator flags this as a notice in the panel. Economically a battery usually stays secondary: in the reference case 82% is used directly anyway — only about 117 kWh of annual surplus could be shifted. It becomes interesting with large module power, such as the 747 kWh export of a 2,000 Wp system.

The yield part covers the DACH region: the hourly grid has 1,155 points at 0.25°, cross-validated against PVGIS. The rules panel reflects German law only (800 W, 960 Wp Schuko, 2,000 Wp, Marktstammdatenregister) — other countries have their own plug-in solar rules. For yields elsewhere, PVGIS by the European Commission (worldwide except polar regions) or NREL PVWatts for the United States are the best official tools; a US grid built on NSRDB hourly data is in preparation.