The battery question comes up in almost every solar consultation we hold since 2023. It generally stems from a sound intuition: if you produce during the day and consume in the evening, why not store? Except that the pure mathematics are not always in the battery's favour, and even less so when you look at proper sizing.
This article attempts an honest answer: yes, a battery can be relevant — sometimes very relevant. But it is not always justified, and it is almost never justified by the payback calculation alone.
How much does a residential battery cost in 2026?
The market has consolidated since 2023. Installed usable-kWh prices in 2026 sit within a narrow band of CHF 1,200 to CHF 1,600 per kWh, management panel and installation included, excluding any inverter replacement.
For a typical installation:
- 5 kWh battery: CHF 6,500 to CHF 8,500
- 7 kWh battery: CHF 9,000 to CHF 11,500
- 10 kWh battery: CHF 13,000 to CHF 16,000
- 13 kWh battery: CHF 16,500 to CHF 21,000
These ranges include a branded lithium iron phosphate (LFP) battery with a manufacturer guarantee of at least 10 years. Installation, cabling, any electrical panel work, and commissioning typically account for CHF 1,500 to CHF 2,500 of the total.
When the PV installation is new and a compatible hybrid inverter is chosen from the outset (Fronius Symo Gen24, Sungrow, SolarEdge), the net additional cost of the battery is limited to the battery itself, with no additional inverter. When a battery is added to an existing PV installation with a standard inverter, a separate battery inverter must often be added (CHF 1,500 to CHF 3,000 extra), or the central inverter must be replaced — which amounts to virtually redoing the electronics side of the installation.
The profitability calculation, honestly
Let us take a standard case. A household in Suisse romande with a 10 kWp PV installation, initial self-consumption of 35 % through natural use. Annual production 9,500 kWh, of which 3,325 kWh self-consumed and 6,175 kWh fed into the grid at 11 ct/kWh.
Without battery:
- Savings on purchases: 3,325 × 0.29 = CHF 964/year
- Feed-in revenue: 6,175 × 0.11 = CHF 679/year
- Annual benefit: CHF 1,643
With an 8 kWh battery raising self-consumption to 75 %:
- Savings on purchases: 7,125 × 0.29 = CHF 2,066/year
- Feed-in revenue: 2,375 × 0.11 = CHF 261/year
- Annual benefit: CHF 2,327
A net gain of CHF 684/year thanks to the battery. For an additional investment of CHF 10,000 installed, the payback is 14–15 years, without accounting for battery degradation or the cost of capital. That is in line with the market average.
This calculation may seem underwhelming — and it is. The battery is not an optimised financial product. It is justified by other things, which need to be named clearly.
The real reasons to invest in a battery
Resilience during outages. With a hybrid inverter and a backup function, a battery allows you to keep the fridge, lighting, internet router, and some sockets running during a grid outage. In rural areas or in a commune where outages recur, this is a real argument that cannot be quantified in CHF but has genuine value.
Pushed self-consumption and partial autonomy. Reaching 80–90 % self-consumption has an almost ideological dimension. Stepping as far as possible away from the grid, no longer watching the monthly bill fluctuate — this is an objective many homeowners pursue independently of the calculation.
Evening coverage in winter. When production falls to 1–2 kWh per day in December, the battery is almost useless. But in mid-season (March–April, September–October), it allows a genuine evening without drawing from the grid. Over six months of the year, the effect is substantial.
Anticipating a future electric vehicle. If an electric car is planned within two to three years and will be charged at home during the day where possible, the self-consumption calculation changes. The battery becomes a useful buffer to shift production towards the night when the EV is not plugged in.
Conversely, not investing in a battery is a perfectly defensible choice for a household with limited daytime consumption and no large shiftable loads.
How to size correctly
Correct sizing is the variable that most changes the outcome. Oversizing wastes capital; undersizing distorts the battery's productivity.
The sound rule of thumb: target between 50 % and 100 % of your average daily consumption in usable storage. A household averaging 12 kWh/day has its optimum between 6 and 10 kWh of battery. Beyond that, you are storing what you would already consume the following morning without a battery, so nothing is gained.
The second criterion is solar production in mid-season, not midsummer. In June, the battery will be full by mid-morning and the surplus goes to the grid. In October, it fills slowly and empties slowly, with almost 100 % useful cycles. It is in mid-season that you optimise the return, not in a heatwave.
Which brands to choose in 2026?
The market is dominated by a few serious players. In Suisse romande, on our recent projects, these are the reliable choices.
BYD HVS / Premium HVS. Probably the most widely deployed residential battery in Suisse romande in 2026. LFP, modular, 10-year guarantee, native integration with most inverters. Good quality-to-price ratio, proven reliability.
LG Resu. A long-standing reference, now LFP (earlier NMC versions were more sensitive), 10-year guarantee, solid ecosystem. Slightly more expensive than BYD for the same capacity.
Fronius Solar Battery. The preferred option if the inverter is a Fronius. Perfect integration, unified monitoring, European manufacture. Higher cost, but simpler maintenance.
Sungrow. Growing strongly since 2024, LFP, competitive pricing, 10-year guarantee. Worth considering to optimise budget without sacrificing quality.
Tesla Powerwall. Still on the market, proprietary ecosystem, higher price, built-in backup function. Suits those wanting the complete Tesla ecosystem (car, storage wall); less so for conventional installations.
To avoid: batteries of unknown brand, bought online, with no Swiss after-sales representation. A failure after five years can mean a battery out of service for lack of parts, and the loss of a CHF 10,000 investment.
The inverter trap
Many homeowners buy a new PV installation without a battery, intending to add storage later. This is a sound approach — provided a hybrid inverter was chosen from the outset.
A hybrid inverter can manage panels and battery in series. A standard inverter cannot. Adding a battery to an existing installation with a standard inverter means either adding a separate battery inverter (with a few percent efficiency loss) or replacing the main inverter, which amounts to virtually redoing the electronic side of the installation.
Our consistent advice: for a new installation, fit a hybrid inverter even if the battery is not ordered immediately. The additional cost (often CHF 500 to CHF 1,200) is recouped at the first battery addition.
Our 2026 verdict
The solar battery, in 2026, is not something we sell by default. It is an investment in comfort and resilience, and incidentally in profitability. We recommend it systematically in three situations:
- A home in a rural area or a commune prone to grid outages, with a genuine backup requirement.
- A household with an electric vehicle and a low daytime consumption profile, where the battery becomes a genuinely useful buffer.
- A PPE with a collective self-consumption scheme (RCP) at a high collective self-consumption rate, where a shared battery can achieve very productive cycles.
In other cases, we present the option and let the client decide, stating clearly that the standalone ROI of the battery is long. Many of our clients take it anyway, for comfort and consistency with their energy approach. That is their right, and it is rarely a poor choice in the long run. It is simply rarely the best purely financial choice.