Savings calculator
Give it your postcode and the calculator pulls the real electricity tariff for your municipality, the price your grid operator pays for your PV electricity, and the sunshine where you live.
The gap between these two prices is what makes a battery pay: the kilowatt-hour you store is one you would have sold at the feed-in tariff. Since 1 January 2026 that tariff has followed a quarterly market price, with a legal floor of 6 ct/kWh. We expect it to fall further in the years ahead.
View the Venus E 3.0What about the other batteries?
Same household, same tariff, same sunshine — only the battery changes. Every plug-in unit is simulated at 600 W on discharge, the Swiss ceiling; installed systems get the best efficiency the HTW Berlin measured, which is the assumption most favourable to them. Prices are real and dated, converted to the kilowatt-hour you can actually use: that is the only way to compare capacities running from 1.6 to 13.5 kWh.
| Battery | Cost per usable kWh | Pays back in | Recovered at 10 years |
|---|---|---|---|
| Venus E 3.0 | CHF 280.– | 5 years and 9 months | 168 % |
| Anker SOLIX Solarbank 3 E2700 Pro | CHF 395.– | 8 years | 123 % |
| EcoFlow STREAM AC Pro, version suisse | CHF 433.– | 9 years | 110 % |
| Anker SOLIX Solarbank 2 E1600 AC | CHF 541.– | 11 years and 10 months | 86 % |
| Batterie de marque, 10 kWh, posée | CHF 861.– | more than 20 years | 44 % |
| Tesla Powerwall 3 | CHF 889.– | more than 20 years | 31 % |
The comparison runs plug & play at 600 W, whichever option you pick alongside.
What this table does not say
- An installed battery is not capped at 600 W: it covers an oven, a hob or a heat pump, which a socket-connected unit does not.
- Some provide backup power during an outage. No socket-connected unit does.
- The “fitting included” prices are ranges collected from Swiss installers, not quotes. Yours will depend on your distribution board.
- Return is not the only reason to buy, and this table compares nothing else.
Public prices recorded in Switzerland on 14 August 2026 for the plug-in units, and ranges published by Swiss installers for installed systems (CHF 6'500 to 9'000 for 10 kWh, Powerwall, BYD and Huawei compared). Beyond ten years the projection assumes tariffs and habits stay put: an indication, not a forecast.
How this figure is obtained
The calculation simulates all 8'760 hours of the year instead of applying an average percentage. Hour by hour it compares what your panels make with what the household uses, fills the battery with the surplus, empties it into the shortfall, and counts what goes in and out at the meter.
- Solar output — PVGIS hourly series for your municipality, roof at 30° facing south, 14 % system losses, terrain shading included. PVGIS 5.3, European Commission.
- Purchase tariff — ElCom 2026 tariff for your municipality’s grid operator, including 8.1 % VAT. ElCom, open data.
- Efficiency — 93 % on charge, 95.5 % on discharge, plus 9 W of electronics while running: a round trip at 300 W returns 84 % of what it took, which is what an independent test on a Venus E 3.0 measured. Technikblog.ch measurement, consistent with the Stromspeicher-Inspektion from HTW Berlin.
- Standby — 8 W around the clock, or 70 kWh a year. On a 2 kWh battery that is more than a tenth of what it gives back.
- Degradation — 2.1 capacity points lost per year, measured over eight years of readings on domestic LFP batteries. Figgener et al., Nature Energy 2024. We do not use the “6'000 cycles” of the data sheets: they state no residual capacity criterion.
- Consumption profile — Switzerland publishes no standard load profile. We build one: night trough, morning peak, a sharper evening peak, a heavier winter. Then we calibrate it against the benchmark from SwissEnergy: a house with panels and no battery self-consumes about 30 % of its output. That is a modelling assumption, not a measurement of your home.
- Control reserve — 3 % taken off the gain, because no real unit reacts as fast as the simulation.
Municipalities and postcodes: official register of localities, ©swisstopo. The full method, sources and limits included.
Non-binding estimate, delivery and subsidies excluded: we deduct no cantonal or municipal grant, so check with your canton — Geneva, for one, has paid a grant since 2026 for batteries of 15 kWh and under. The result depends on your real consumption profile, on how your panels face and on how tariffs move, which nobody can guarantee over ten years.
What the calculation assumes
The assumptions behind the result, line by line.
| Purchase tariff | ElCom 2026 tariff for your municipality, including 8.1 % VAT. Without a postcode: 30.1 ct/kWh, the median of 2107 Swiss municipalities. |
| Feed-in tariff | The tariff published by your grid operator, or failing that the legal minimum of 6 ct/kWh. |
| Solar output | PVGIS hourly series for your municipality, roof at 30° facing south, 14 % losses. Swiss median: 1117 kWh per kWp per year. |
| Efficiency | 93 % on charge, 95.5 % on discharge, plus 9 W of electronics while running — 84 % round-trip at 300 W. |
| Standby | 8 W around the clock, or 70 kWh a year. |
| Depth of discharge | 90 % of the rated capacity. |
| Degradation | 2.1 capacity points a year, measured on domestic LFP batteries. |
| Control reserve | 3 % taken off the gain. |
| Horizon | 10 years. |
| Subsidy deducted | None. |
| Delivery cost | Not included. |
One point changes everything, and most calculators slide past it: a stored kilowatt-hour does not earn you the full tariff. You would have sold it to the grid. What it earns you is the gap between what you pay and what you would have been given for it — about 24 centimes in the median municipality. Costing it at the full tariff would inflate the result by half.
What the calculation does not do: it ignores off-peak and peak arbitrage, which improves the result where the supplier uses time-of-use tariffs; it does not know exactly how your panels face, nor your real consumption profile. And it assumes tariffs hold steady, which nobody can promise over ten years — since January 2026 the feed-in tariff has followed the quarterly market price.