Will a battery pay back?
Jason Hawthorne, CEO at ESME
Rates checked October 2026 · 6 min read · Last updated 22 October 2026
In short
It can, but not always. A battery pays back when the money it saves each year adds up to its price before it wears out, usually in 10 to 12 years. With a cheap overnight tariff and a fair price, payback of 6 to 14 years is common. A high price or low evening use can push it past the battery’s life.
For your house
Would a battery pay back at your house?
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Key facts
What it earns
The gap between your cheap rate and the 26.32p price cap rate
Usual lifespan
10 to 12 years, with warranties often 10 years
Lost on the way in and out
About a tenth of the energy
5kWh example
About £316 a year, 6 to 15 years to pay back
10kWh example
About £569 a year, 9 to 14 years to pay back
How do I work out payback?
- 1Find the units it will shift each day. That is your use outside the cheap hours, up to the battery’s usable size.
- 2Work out the saving per unit. The price you avoid, less the cheap rate grossed up for losses. At 26.32p and 8p, that is about 17.3p a unit.
- 3Multiply up to a year. Units a day, times the saving per unit, times 365.
- 4Divide the price by the yearly saving. That is the payback in years. Compare it with the battery’s life and warranty.
What does that look like in practice?
Units shifted a day
5kWh battery
5
10kWh battery
9, a home with an electric car
Saved a year
5kWh battery
About £316
10kWh battery
About £569
Typical price
5kWh battery
£2,000 to £4,600
10kWh battery
£5,000 to £8,000
Years to pay back
5kWh battery
About 6 to 15
10kWh battery
About 9 to 14
Using the 26.32p price cap rate from 1 October 2026 and an 8p overnight rate, with about 11% lost in charging. Prices from the Energy Saving Trust and an installer price guide, August 2026.
What makes the answer change?
- The price cap. If it rises, each unit shifted saves more. Ofgem announces the January 2027 cap on 25 November 2026, and one forecaster expects a rise of about 16%.
- Your tariff. An electric car tariff at 7p to 8p roughly doubles the saving of a 16p overnight rate.
- Solar. Free summer charging adds to the saving, see solar first, or a battery.
- VAT. There is no VAT on batteries until 31 March 2027. After that it returns to 5%.
Questions people also ask
How long do home batteries last?
Usually 10 to 12 years, and warranties are often 10 years. They slowly hold less charge as they age.
Do batteries pay back faster with solar?
Often, yes, because sunny days fill them for free. In winter most of the charge still comes from the grid.
Is a battery worth it if prices fall?
The saving depends on the gap between cheap and normal rates, not the level of prices. If the gap narrows, payback gets longer.
Sources
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Figures are for Great Britain and were checked on the date above. Prices change, so check the latest before you decide. This is general information, not financial advice.
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