Is a balcony solar kit worth it in 2026? The sum in years
A 900 Wp kit costing €450, hung upright facing south, saves a household using 2,500 kWh €152 a year on the German average and pays for itself after 3.0 years. On a north side it takes 7.7 years.
Checked by Radif Partners · Editorial policy · How we calculate
How many years until your balcony system pays for itself
Payback
3.0 years
| Saving per year (900 Wp upright south) | €152 |
| Saving over 20 years | €3,041 |
| Net gain after 20 years | €2,591 |
Whether a balcony power plant (Balkonkraftwerk) is worth it comes down to one division: purchase price divided by the annual saving. The saving is the power the household uses itself, times its own electricity price; the surplus goes to the grid without payment. With 900 Wp upright on a south-facing railing, a device produces 656 kWh on the German average, of which a household using 2,500 kWh consumes 420 kWh itself. At 36.2 ct/kWh that is €152 a year, so a kit costing €450 pays back after 3.0 years and one costing €1,000 after 6.6 years. Over 20 years the saving adds up to €3,041. It stops paying when several drawbacks combine: facing east, with 40 per cent shade and only 1,000 kWh of consumption, the same device saves €54 a year, and a kit costing €700 then needs 12.9 years.
The formula behind payback
A balcony kit does not earn money; it avoids buying power. Every kilowatt-hour that the fridge, router, washing machine or home office takes straight from the balcony does not appear on the bill. The rest flows through the meter to the grid and earns nothing, because section 8(5a) EEG assigns plug-in devices to unpaid acceptance. The annual saving is therefore self-used power times the electricity price, and payback is price divided by saving. How much a household consumes at the moment of generation is simulated by the engine with metered load profiles of 74 households from HTW Berlin; generation comes from PVGIS, and the power price of 36.2 ct/kWh from the Eurostat statistics for German households.
Lever one: the purchase price
| Purchase price | Saving per year | Payback | Net gain after 20 years |
|---|---|---|---|
| €300 | €152 | 2.0 years | €2,741 |
| €450 | €152 | 3.0 years | €2,591 |
| €700 | €152 | 4.6 years | €2,341 |
| €1,000 | €152 | 6.6 years | €2,041 |
Price works linearly: double the price, double the wait. Mounting material belongs in it, meaning brackets, cable and, where wanted, a dedicated Wieland socket fitted by an electrician. If you mount it yourself on a simple railing bracket, you usually stay in the first two rows.
Lever two: when you use power
What matters is not annual consumption as such but what runs in daylight. A household using 1,000 kWh takes 257 kWh from the same device, one using 2,500 kWh 420 kWh and one using 5,000 kWh 541 kWh. If you work from home, start the dishwasher at noon or run an aquarium, you are near the top. If you are out on weekdays, you are near the bottom; a timer for washing machine and dryer then does more than any extra panel.
Lever three: direction and shade
| Facing (upright) | Output | Saving | Payback at 450 € |
|---|---|---|---|
| south | 656 kWh | €152 | 3.0 years |
| south-west | 635 kWh | €147 | 3.1 years |
| east | 410 kWh | €104 | 4.3 years |
| west | 485 kWh | €122 | 3.7 years |
| north | 174 kWh | €58 | 7.7 years |
South and south-west are almost level; east and west lose a third of output but less of the saving, because morning and evening power is used at home more often: facing east €104 instead of €152. The north side falls far behind. Shade from the house opposite, a tree or the balcony above acts as a deduction from output; orientation in detail is covered under plug-in solar orientation.
Lever four: the power price over the years
At a flat price the example device brings €3,041 over 20 years. If the power price rises by 2 per cent a year, it is €3,694. Conversely a cheap tariff stretches payback: at 30 ct/kWh you wait 3.6 years, at 45 ct/kWh 2.4 years.
When it does not pay
A single drawback rarely tips the sum. It becomes critical when several combine: an east balcony, a tree in front that takes 40 per cent of the sun, and a single household that barely uses power in daylight. A kit costing €700 then saves only €54 a year and pays back after 12.9 years. A planned move to a flat without a balcony also stretches the sum; what applies then is under plug-in solar for tenants. Expensive battery bundles only pay if they last long enough; the comparison is under plug-in solar with battery. If you know your location, use the postcode in the calculator, since the same device in Munich produces 14 % more than in Flensburg: 727 instead of 635 kWh (plug-in solar yield).
What the sum leaves out
The payback above describes good conditions; it is not a guarantee. Three things are not in it. First, panels age: their output declines slightly over the years, which barely shifts break-even when payback is short but trims the net gain after 20 years. Second, an inverter often does not last as long as the panels. If it has to be replaced after some years for an assumed €200, the total price in the example rises to €650 and payback stretches to 4.3 years. Third, your own work is not counted: mounting, registering and the odd wipe of the panels cost time, not money.
On the other hand, some effects in your favour are left out too. With power prices rising 2 per cent a year, the example recovers its price in year 3. And if you deliberately shift appliances to midday, you raise your self-used share above the average of the metered households.
How to check your own numbers
Take your last annual bill (Jahresabrechnung): it shows consumption and the unit price (Arbeitspreis) in cents per kilowatt-hour, without the standing charge, which you keep paying anyway. Enter both and the price of the offer into the mini calculator. Under five years, the device is a good deal in almost any case. Between five and ten years, take a second look at shade and mounting spot. Above that, a different place on the building often helps more than a cheaper kit.