How long does a solar battery take to pay for itself?
About 11 and a half years for a £5,000 battery, if it is planned: the price divided by one modelled year’s average saving, not a forecast. Across 20 modelled homes, a planned 9.5 kWh battery saved £435.48. Left to itself, £170.99, which takes 29 years, longer than it lasts.
What these figures rest on: 20 London households’ real smart meter readings (Low Carbon London) with a modelled 9.5 kWh battery and 4 kWp of panels, and again with 13.5 kWh and 6 kWp, on the prices Octopus published and the sun that came, planned on the forecasts as issued, 1 October 2025 to 30 September 2026. How Orza is tested.
Every £1,000 a battery costs takes 2.3 years to earn back, planned.
Payback here is the price divided by the average saving of one modelled year, not a forecast of when yours pays for itself. The saving is against the same home, panels and tariff with no battery, a home already paid for its export. Left to itself, the same £1,000 takes 5.85 years.
Years to pay back, average home, 9.5 kWh battery
- £3,000 battery: 6.9 years planned17.5 years left to itself.
- £5,000 battery: 11.5 years planned29.2 years left to itself.
- £7,000 battery: 16.1 years planned40.9 years left to itself.
Already have a battery? Orza plans it to pay back sooner.
Free, with no card: an email and a password, and you look round an example home first. Connect your battery through its maker’s cloud when you’re ready, or never. It starts in Monitor only, and nothing is sent to it until you choose.
Within its life, only if it is planned.
The Energy Saving Trust puts a battery’s life at about 10 to 12 years. Here is how many of the 20 homes earned back each price within 10 years.
| Price of the battery | 9.5 kWh, left to itself | 9.5 kWh, planned | 13.5 kWh, planned |
|---|---|---|---|
| £3,000 | 17.5 years, 0 of 20 homes | 6.9 years, 20 of 20 | 5.5 years, 20 of 20 |
| £5,000 | 29.2 years, 0 of 20 | 11.5 years, 3 of 20 | 9.1 years, 17 of 20 |
| £7,000 | 40.9 years, 0 of 20 | 16.1 years, 1 of 20 | 12.8 years, 1 of 20 |
Each cell: years for the average home to pay back that price, then how many of the 20 homes paid it back within 10 years. A year’s saving at the prices of 1 October 2025 to 30 September 2026, with nothing for fade or price changes. Each home on whichever of five Octopus tariffs cost it least, with the battery and without: with one planned, 17 of the 20 stayed on Agile with Outgoing Octopus and three did best on Flux. Held on Agile with Outgoing Octopus, all 20 saved £431.13, the figure other guides quote from the same test. 9.5 kWh with 4 kWp of panels; 13.5 kWh with 6 kWp. Standing charges are left out, and no limit was put on export.
- The homes differed by two to onePlanned, the 9.5 kWh battery saved £356.09 to £711.49 a year, depending on the home. At £5,000 that is 7.0 to 14.0 years.
- For a three year payback, the price has to be under about £1,300For the average home, planned. Under about £500 left to itself.
- The bigger battery paid back sooner13.5 kWh with a bigger roof saved £547.29 a year planned, 1.83 years for each £1,000, but it costs more to buy. What size battery for your home.
Divide your quote by the saving.
The sum works for any price. Take the installed price on your quote and divide it by what the battery saves in a year: £435.48 planned or £170.99 left to itself for these homes, or your own figure if you have one. Then set the years against the 10 to 12 the Energy Saving Trust gives a battery.
Worked through, average home, 9.5 kWh
- A £4,000 quote: 9.2 years planned£4,000 divided by £435.48. Left to itself, £170.99 gives 23.4 years.
- A saving a tenth lower: 12.8 years at £5,000A fifth lower, 14.4. The same sum, so you can try your own.
- Whether it is worth it is a different questionWhat it adds up to over a battery’s life, and what to check before you buy. Is a solar battery worth it?
What makes yours sooner or later.
A year of modelled homes is strong evidence, not a quote: real meter readings from 20 London homes, with a modelled roof and battery.
- Prices from here onPayback here is at one year’s prices. Dearer power shortens it, cheaper lengthens it.
- The battery getting olderA battery holds a little less each year, so later years save a little less, and a battery worked harder ages a little faster. Does charging and discharging wear it out?
- Your use, tariff, sun and export limitThese homes used 3,400 to 13,000 kWh a year, half of them over 4,700. What moves the saving for your own home.
- The seasonThe saving doesn’t come evenly through the year. A battery in winter, and in summer.
Battery cost and life: the Energy Saving Trust’s battery storage advice, last updated 6 October 2026. The prices of £3,000, £5,000 and £7,000 are examples inside its range. Tariff prices as Octopus published them for North West England.
Before you count the years.
What changes the answer for your home.
All our guidesGet more from your battery
How Orza is tested
How long does a solar battery take to pay back in the UK?
Dividing the price by one modelled year’s average saving, across 20 homes with a 9.5 kWh battery planned to the prices: 6.9 years at £3,000, 11.5 at £5,000 and 16.1 at £7,000. Left to itself, the same sum gives 17.5 to 40.9 years. It is arithmetic, not a forecast.
Does adding a battery to existing solar panels pay back?
The figures here are for exactly that: the saving is against the same home and panels with no battery, already paid for export. Whether it pays back within the battery’s life depends mostly on its price and on whether it is planned.
Can a battery pay back without solar panels?
It can save money on its own, filled when power is cheap. What a battery with no panels made over a year.
Does a bigger battery pay back faster?
Per £1,000, yes, in these homes: 13.5 kWh with 6 kWp of panels took 1.83 years for each £1,000 against 2.30 for 9.5 kWh with 4 kWp. But it costs more, so the years depend on the price you are quoted.
What does Orza cost?
Nothing right now: everything is free while we spread the word, and no card is needed to join. Paid tiers will come later, and there will always be a free version.
The same battery, paying back in less than half the time.
Free, with no card. Look round an example home first, and connect your battery when you’re ready.