Solar battery storage cost: what you'll really pay in 2026

The headline numbers

United States. EnergySage, which runs a large marketplace for solar and battery quotes, puts the typical installed price of a Tesla Powerwall 3 at about $13,473 before incentives in 2026. That’s $998 per kWh for its 13.5 kWh of storage, and EnergySage says it’s about 13% below the average battery on its marketplace. Across brands and installers, prices typically run from about $700 to $1,300 per kWh of usable capacity.

United Kingdom. The government publishes the price of every MCS-certified battery installed in existing homes. For April 2025 to March 2026, covering more than 42,000 installations:

Those prices include the battery, installation, connection and VAT where it applied, and exclude solar panels. Multiply the median by the size you want to get a benchmark: a 10 kWh battery at £890 per kWh is about £8,900. Many quotes come in well below the median, especially from larger installers and energy suppliers, so treat it as a ceiling check rather than a target.

What’s in a battery quote

A battery quote is more than a box on the wall. Expect to see:

• The battery itself, usually the biggest single item.
• An inverter or gateway. Some batteries have one built in. Others need a separate hybrid inverter or a backup gateway that disconnects your home from the grid in an outage.
• Electrical work. Moving essential circuits to a backup subpanel, upgrading the main panel if it’s full or old, and running cables to wherever the battery goes.
• Permits and inspection in most US areas, and notification to the network operator in the UK.
• Commissioning and app setup, including registering the warranty.

When two quotes for the same battery differ by thousands, the electrical work is usually why. Ask each installer to itemize it.

Compare price per usable kWh

Divide the total price by the battery’s usable capacity, not its nominal or “total” capacity, which can be 5 to 10% higher. Then check two more things on the spec sheet:

• Power (kW). A cheap battery per kWh with low output may not start your well pump or air conditioner.
• Warranty. Look at the years, the guaranteed capacity at the end, and any limit on total energy throughput. A warranty that runs out early on throughput is effectively shorter if you cycle the battery daily.

The costs nobody lists

Round-trip losses. About 10% of the energy you put in doesn’t come back out. If you charge from the grid, that’s 10% more electricity to pay for.

Capacity fade. Batteries lose capacity slowly. Warranties commonly guarantee around 70% after about ten years.

The cost of storing a kWh. Here’s a sum installers rarely show. A $13,500 battery holding 13.5 kWh, cycled every day for ten years at an average of 85% of its original capacity, delivers roughly 42,000 kWh. That works out to about 32 cents for every kWh it stores and gives back, before the cost of the electricity itself. In the UK, a 10 kWh battery at the £890 median works out to roughly 29p per kWh stored. If your peak and off-peak prices aren’t that far apart, daily cycling alone won’t pay the battery back. Backup value, solar self-use and utility payments have to make up the rest.

Replacements and repairs. Separate inverters often have shorter warranties than batteries. Ask what’s covered and for how long.

Incentives in 2026

US: The 30% federal tax credit for home batteries ended under the One Big Beautiful Bill Act, and batteries placed in service in 2026 generally don’t qualify. What’s left is state rebates, utility incentives and performance payments. New England’s ConnectedSolutions program, for example, pays battery owners per kilowatt they supply during summer peak events. Search the DSIRE database for your state.

UK: Installed batteries are zero-rated for VAT until 31 March 2027, whether fitted with solar or on their own. Some energy suppliers also run tariffs and events that pay batteries for exporting at peak times.

Does a battery pay for itself?

For solar homes, a battery lets you use more of your own daytime power in the evening instead of exporting it cheaply, and that’s where most of the savings come from. With a good time-of-use tariff or a utility program on top, payback in the region of ten years is achievable. Without any of those, especially on a flat-rate tariff, the battery mostly buys you backup and independence, and those don’t show up on a spreadsheet.

If you don’t have solar, the numbers are tougher. Our guide to battery backup without solar works through them.

How to get a fair quote

1. Get at least three quotes, priced per usable kWh.
2. Ask each installer to separate the battery price from the electrical work.
3. Compare against the benchmarks above: around $1,000 per kWh in the US, or the DESNZ medians in the UK.
4. Read the warranty: years, end capacity and throughput.
5. Ask what happens in an outage: which circuits stay on, and how quickly the switchover happens.

To decide how big a battery you need in the first place, see whole-home or essentials only?.