Is home battery storage worth it in 2026?

Guide · Published by SEO Dons Ltd · Updated 28 September 2026

The four numbers that decide it

1. The price per kWh. The official medians for MCS-certified batteries fitted in 2025/26 were £1,300 per kWh under 6 kWh, £890 for 6 to 11 kWh and £630 for 11 kWh or more. Large suppliers publish lower package prices: Octopus lists about 10 kWh battery-only from £5,336, roughly £521 per kWh.
2. The tariff. A battery earns on the gap between what you pay for the electricity that goes in and what you would otherwise pay, or be paid, for it. The size of that gap is set almost entirely by the tariff.
3. Your evening use. A battery only saves on energy it empties. A home that uses little after dark cannot use a large battery.
4. Solar. Panels give the battery free energy to store, and open up tariffs such as Octopus Flux that need solar.

Payback, tariff by tariff

This site’s savings model, for a 10 kWh battery in a home using 3,000 kWh a year, with 4 kWp of solar where stated, using each region’s rates for 26 September 2026:

Simple payback: price divided by the first-year saving, before any change in rates. Battery warranties run 10 to 15 years.

The table tells the story. On a flat tariff a battery does not pay back within any warranty. On a good time-of-use tariff, at a supplier’s package price (the supplier comparison lists them), it roughly pays back by the end of its warranty. At the official median price, even the best case runs past it. The payback falls a little with an electric car, but that tariff is aimed at EV owners.

Why the tariff matters so much

On a flat tariff, a battery can only do one thing: store surplus solar for the evening. Each kWh stored avoids buying a kWh at the flat rate (26.35p in London on 26 September 2026) but gives up the 12p export payment it would have earned, and loses about a tenth in the round trip. That is worth roughly 12p to 14p per kWh, and in winter there is little surplus to store.

On a time-of-use tariff the battery also charges from the grid when power is cheap. Octopus Flux’s gap between its 2am to 5am rate and its 4pm to 7pm rate is 19.37p to 21.44p per kWh depending on region, and its peak export rate, about 27p to 31p, lets a battery sell spare energy at the dearest time of day. Octopus Go’s overnight rate is 8.62p against a daytime rate of 29.42p to 32.28p. That is why the same battery saves roughly two and a half times as much on Flux as on a flat tariff.

Export is the other half of a time-of-use tariff. What each tariff pays is set out in Octopus export tariffs compared, from 4.1p a unit on the Smart Export Guarantee tariff to about 31p in the Flux evening peak.

When a battery is worth it

• You have solar and can join Octopus Flux or a similar time-of-use tariff, and the price is near or below the median for the size.
• You have an electric car on an overnight tariff, so the battery can run the house on cheap-rate power through the day.
• You use a lot after dark: a heat pump, electric heating or a large household.
• You value backup and are prepared to pay for the hardware that provides it.
• You expect to stay for ten years or more, so the saving has time to accumulate.

If home battery backup is part of the reason, price it as a separate line. Ofgem’s data put the average Great Britain interruption in 2024/25 at about 88 minutes, so the essentials need well under a kilowatt-hour; what costs money is the hardware that makes backup possible.

A battery fitted with new panels usually costs less than one added later, because the inverter, the visit and the paperwork are shared; solar battery storage sets out what a combined price covers.

When it probably is not

• You will stay on a flat tariff. In the model a 10 kWh battery with solar saves £141 to £181 a year on a flat tariff for a 3,000 kWh home, which does not repay it within its warranty at any published price.
• Your use is low. A home using 1,800 kWh a year saves £131 with 5 kWh on a flat tariff in the model, and nothing more with a bigger battery. See what size battery you need.
• The quote is well above the median for its size. The quote checker shows where yours sits.
• You may move within a few years, or you rent.
• The payback relies on a tariff you cannot join. Octopus Flux needs solar panels, and Intelligent Octopus Flux is currently limited to customers who bought solar and a battery from Octopus.

The clearest case is a battery in a home with no solar. On 12 months of real Agile prices a 10 kWh battery would have saved £239 to £266 a year on its own for a 3,000 kWh home, which is 20 years or more to repay at Octopus’s published £5,336.

The risks that change the answer

• Tariffs change. The Tesla Energy Plan tariff has been retired in the UK, and Octopus has limited Intelligent Flux to its own installation customers. A payback that depends on one tariff’s export rate carries that tariff’s risk.
• The VAT cut on electricity. VAT on household electricity is removed from 1 October 2026 to 31 March 2027, lowering import rates by about 4.8% if passed on in full, which trims a battery’s saving by a few percent while it lasts.
• The maker can fail. GivEnergy entered administration in April 2026 and its administrator has said hardware warranties will not be honoured. See what happened to GivEnergy and the GivEnergy battery page.
• Capacity fades. A multi-year study of 21 home batteries in Germany found an average loss of about 2 to 3 percentage points of usable capacity a year. The model allows for capacity averaging 90% of new over ten years.
• A battery wears out before the panels. The Energy Saving Trust puts a typical battery’s lifespan at about 10 to 12 years. See how long batteries last.

What helps

Installed batteries in homes carry 0% VAT until 31 March 2027 under HMRC’s VAT Notice 708/6, including standalone batteries and batteries added to existing solar. There is no national battery grant, but the Warm Homes Plan’s loan scheme and some local schemes can help; see grants, VAT and funding, and what the Warm Homes Local Grant’s £16,600 cap means for a household. The biggest lever is the price: the difference between a quote at the median and one at a large supplier’s package price is about £3,500 on a 10 kWh battery, and it moves the payback by eight years or more.

Deciding for your own home

Run your own region, usage, solar and tariff through the calculator, then test the answer against real prices. Two or three battery storage quotes on the same usable capacity will show you what a battery actually costs for your home, and the line-by-line checklist shows how to compare them. If the numbers do not work today, they may after a tariff change, a new car or a heat pump.

Before you decide, price the whole system. The solar panels and battery cost guide sets the published packages against DESNZ’s official figures and models how long the panels and the battery each take to repay, and the solar battery cost guide covers the battery alone.