A home battery installed in the UK costs a median of £1,300 per kWh under 6 kWh, £890 per kWh for 6 to 11 kWh and £630 per kWh above that, according to DESNZ figures for MCS-certified installs between April 2025 and March 2026. That is roughly £6,500 for 5 kWh, £8,900 for 10 kWh and £8,505 for 13.5 kWh. The average installation in each band cost roughly £6,600, £8,500 and £10,400. Suppliers' standard packages start lower: Octopus lists 10 kWh battery-only from £5,336.
The official figures: median installed price per kWh
The Department for Energy Security and Net Zero publishes the price of every MCS-certified battery installation in existing homes. The price covers the battery, installing and connecting it, and VAT where it applied; it excludes solar panels and other work done at the same visit. These are the medians:
| Battery size | Median, 2025/26 | Mean, 2025/26 | Median, 2024/25 | Sample size |
|---|---|---|---|---|
| Battery under 6 kWh | £1,300/kWh | £1,280/kWh | £1,080/kWh | 16,270 |
| Battery of 6 to 11 kWh | £890/kWh | £870/kWh | £910/kWh | 14,457 |
| Battery of 11 kWh or more | £630/kWh | £670/kWh | £590/kWh | 12,176 |
Two things stand out. The price per kWh falls steeply with size, because installation labour and the electrical work are much the same whether the battery is 5 kWh or 13.5 kWh. And small batteries got dearer per kWh in 2025/26 while large ones barely moved, which fits a market shifting towards bigger systems and a small-battery price that is mostly labour.
What the average installation looked like in 2025/26
A price per kWh is not a price you pay. DESNZ also publishes the total capacity of the batteries in each band, so dividing it by the number of installations gives the average size, and multiplying that by the band's mean price per kWh gives a rough price for the average installation. The figures are rounded in DESNZ's tables, so read the last column as a guide to the nearest £100.
| Band | Installations in sample | Change on 2024/25 | Share of the sample | Average size | Mean price per kWh | Roughly, the average installation |
|---|---|---|---|---|---|---|
| Battery under 6 kWh | 16,270 | +55% | 38% | 5.1 kWh | £1,280 | £6,600 |
| Battery of 6 to 11 kWh | 14,457 | +71% | 34% | 9.8 kWh | £870 | £8,500 |
| Battery of 11 kWh or more | 12,176 | +147% | 28% | 15.5 kWh | £670 | £10,400 |
Two readings. The typical household did not buy 13.5 kWh: the largest band's average battery was 15.5 kWh, and that band grew fastest, from 21% of the sample to 28%. And the median price per kWh moved by +20%, -2% and +7% across the three bands while installations rose 80%, and by the same rough calculation the average installation in each band cost 8%, 2% and 5% more than a year earlier, from slightly higher mean prices per kWh in two of the bands and slightly larger batteries in all three.
What that means for the sizes people buy
Multiplying the median per kWh by the size gives a benchmark total. It is a benchmark, not a quote: half of the installations in each band cost more and half cost less.
| Usable size | At the official median | A published price at this size | Modelled saving a year* |
|---|---|---|---|
| 5 kWh | £6,500 | Octopus, Fox EVO 5 or Enphase IQ Battery 5P, battery only: from £3,947 | £174 |
| 10 kWh | £8,900 | Octopus, Fox EVO 10 or two Enphase IQ Battery 5P, battery only: from £5,336 | £414 |
| 13.5 kWh | £8,505 | Octopus, Tesla Powerwall 3, battery only: from £7,999 | £569 |
| 15 kWh | £9,450 | No supplier publishes one; usually three modules of about 5 kWh | £626 |
| 20 kWh | £12,600 | Two units or a stacked system; get it itemised | £731 |
The sizes table adds the 12 kWh and 16 kWh steps and sets every size's published price and modelled saving side by side. The last column is why size matters more than price per kWh. Doubling from 10 kWh to 20 kWh roughly doubles the benchmark price but adds far less to the modelled saving, because a typical home cannot empty the extra capacity every day. The calculator runs the same comparison with your own usage and region.
The 11 kWh price cliff
Because DESNZ's median falls at the edge of its bands, the benchmark total can go down as the battery gets bigger: 10 kWh at £890 per kWh is £8,900, while 13.5 kWh at £630 per kWh is £8,505, £395 less for 35% more capacity. It is an artefact of how the bands are cut rather than a pricing rule, since the 11 kWh and over band averages 15.5 kWh, but it is why 13.5kWh batteries are priced closer to 10 kWh ones than the size suggests. Check any quote near the edge of a band against both medians.
Published prices from UK suppliers
These are prices suppliers state on their own pages. Most are "from" prices for a standard installation, so a survey can add to them.
| Published by | What it covers | Price | Date |
|---|---|---|---|
| Octopus Energy | Battery only, about 5 kWh (a Fox ESS EVO 5 or one Enphase IQ Battery 5P) | from £3,947 | April 2026 prices |
| Octopus Energy | Battery only, about 10 kWh (one Fox ESS EVO 10 or two Enphase IQ Battery 5P) | from £5,336 | April 2026 prices |
| Octopus Energy | Battery only, Tesla Powerwall 3 (13.5 kWh) | from £7,999 | April 2026 prices |
| Octopus Energy | Extra 13.5 kWh Tesla Expansion Pack, fitted with the Powerwall 3 | £3,773 | April 2026 prices |
| Octopus Energy | Same Expansion Pack added to an existing Powerwall 3 later | £5,909 | April 2026 prices |
| E.ON Next | Home battery on its own (5.12 kWh, 4.6 kWh usable) | from £3,995 | checked 27 September 2026 |
| E.ON Next | Battery added at the same time as E.ON Next solar panels | from £1,900 | checked 27 September 2026 |
| Tesla (hardware list price) | Powerwall 3 with Backup Gateway 2, before VAT, delivery and installation | £5,975 | checked 27 September 2026 |
| Energy Saving Trust | Typical home battery price range; about £4,600 for 5 kWh | £1,500 to £10,000 | updated 19 August 2026 |
| MoneySavingExpert | Standard home battery system | about £1,500 to £10,000, around £5,000 on average | updated 4 August 2026 |
| Heatable (median of its quotes) | Battery added to existing solar | median £6,500 (range £6,000 to £8,500) | updated 18 June 2026 |
| Heatable (median of its quotes) | New solar panels plus battery | median £10,500 (range £10,000 to £12,500) | updated 18 June 2026 |
| MCS | Average battery storage installation, all sizes, 2025 | around £9,000 | 2025 figure |
| Octopus Energy | Package: 12 solar panels plus a 10 kWh battery | £11,115 | April 2026 prices |
| Good Energy | Package: 10 solar panels plus Tesla Powerwall 3 with power-cut protection | from £13,900 | checked 27 September 2026 |
Where the money goes in a quote
A quote is one number, but it is a box plus everything needed to make it work on your wall. For one product the two parts are public. Five UK retailers listed the Fox ESS EVO 10 (a 5 kW inverter and 10.24 kWh of battery) at £2,880 to £3,356 before VAT on 7 October 2026, and Octopus's installed price for about 10 kWh, which it fits with that unit or two Enphase batteries, is £5,336 with no VAT. On that comparison the hardware is about 54% to 63% of the installed price, and the other £1,980 to £2,456 pays for the survey, fitting and wiring, commissioning, the network notification, certification, the warranty route and the supplier's margin. A supplier buying in volume pays less than a retail listing, so the split is indicative; the worked example is in how much of a Fox EVO installation is hardware.
Tesla's Powerwall 3 shows the same pattern from the other side: its UK list price is £5,000, or £5,975 with the Backup Gateway 2, before VAT, delivery and installation, and the four installed prices published in October 2026 run from £7,795 to £8,499.99. Buying hardware yourself is rarely the saving it looks like: supply-only batteries carry 20% VAT, the installed supply is zero-rated, and the Tesla and Fox warranties both depend on who installed the battery.
Adding a battery later costs more than fitting it with solar
The pattern in suppliers' own prices is consistent. E.ON Next lists batteries from £1,900 when they go in with its solar panels, against from £3,995 on their own. Octopus prices an extra 13.5 kWh Tesla Expansion Pack at £3,773 when it is fitted with a new Powerwall 3 and £5,909 when it is added to one later. Heatable's median quotes put a battery added to existing solar at £6,500 and a new solar-plus-battery system at £10,500.
The reasons are practical: one site visit, one electrical connection, one network notification and, for a new system, one hybrid inverter that serves both the panels and the battery. A battery added to older panels usually needs its own inverter. See adding a battery to existing solar, solar panels with a battery and the solar panels and battery cost guide for combined prices.
The extras that push a quote up
- Backup hardware. Keeping power on in a cut needs extra equipment. Tesla's own list prices show the effect: Powerwall 3 is £5,000 without Backup Gateway 2 and £5,975 with it, before VAT and installation.
- Consumer unit (fuse box) work. The Eco Experts puts a fuse box at £400 to £800 in its solar hidden-costs table. Older boards sometimes need replacing to take a new circuit.
- A compliant location. PAS 63100 prefers outdoors and rules out bedrooms, escape routes, lofts and cellars without outside access. An indoor room needs 30-minute fire separation and ventilation to outside, so the right spot may mean a longer cable run or building work. PAS 63100 explained.
- A network application. Small systems are notified to the network operator after installation under G98. Larger inverters, or solar plus battery above 3.68 kW on a single phase, need a G99 application first, which takes time and sometimes an export limit.
- Scaffolding only applies when panels are going on the roof; a battery on its own does not need it.
What finance adds to the price
Paying over time raises the total. E.ON Next's published example for its £3,995 battery is a £998.75 deposit and 120 monthly payments of £35.77 at 7.9% APR representative, which comes to £5,291.15, £1,296.15 or 32% more than the cash price. Compare the total repayable, not the monthly figure. A government-backed loan scheme exists for 2026, with lenders passing a grant on as a lower rate and a £15,000 cap for a battery; its rules, and the grants that can pay for part of a battery outright, are on the grants and funding page.
VAT on home batteries
Installed batteries in homes are zero-rated until 31 March 2027 and 5% from 1 April 2027, under HMRC VAT Notice 708/6. Since 1 February 2024 that covers batteries retrofitted to solar and standalone batteries charged from the grid. A battery bought without installation is charged at the standard rate, which is one reason a supply-only price is not comparable with a fitted one. More on VAT, grants and loans.
The cost of a delivered kWh, and what a battery repays
Capacity is what the price buys; delivered electricity is what you use. Dividing the price by the kWh a battery hands back to the house over ten years gives, in this site's model for a London home with 4 kWp of solar on Octopus Flux, 18.0p per delivered kWh for a 10 kWh battery at Octopus's £5,336, against a modelled earning of 12.6p per delivered kWh, and 30.1p at the official median price. The result is a simple payback of about 13 years at Octopus's prices for 10 kWh, about 14 for a Powerwall 3 and 25 or more on a flat tariff. The working is in what a delivered kWh from a home battery costs.
How to check your own quote
Divide the price by the usable capacity and compare it with the median for that size, then check what the quote includes: usable kWh, inverter power, backup, location, warranty and the network paperwork. The quote checker does the arithmetic and models the saving; the comparison checklist lists what to ask for in writing. If you only have one price, asking for more battery storage quotes is the simplest way to see whether it is fair.
Home battery cost questions
How much does a solar battery cost in the UK?
The official median installed price between April 2025 and March 2026 was £1,300 per kWh for batteries under 6 kWh, £890 per kWh for 6 to 11 kWh and £630 per kWh for larger batteries (DESNZ, MCS-certified installs in existing homes). At those medians a 5 kWh battery is about £6,500, a 10 kWh battery about £8,900 and a 13.5 kWh battery about £8,505. Large suppliers publish lower "from" prices for standard packages.
What is the average cost of a solar battery in the UK?
In 2025/26 the average MCS-certified installation in each DESNZ band was 5.1 kWh at roughly £6,600, 9.8 kWh at roughly £8,500 and 15.5 kWh at roughly £10,400, using each band's mean price per kWh. MCS puts the average across all sizes at around £9,000 for 2025.
How much does a 10kWh battery cost?
Octopus lists a battery-only installation of about 10 kWh (a Fox ESS EVO 10 or two Enphase IQ Battery 5P) from £5,336 at April 2026 prices. At the official median of £890 per kWh for 6 to 11 kWh it is about £8,900, and the average battery in that band, 9.8 kWh, cost roughly £8,500. Supplier packages come in below the median; bespoke jobs come in above it.
Is it cheaper to add a battery when the solar panels go in?
Usually. One visit, one inverter and one set of paperwork cover both. E.ON Next, for example, lists batteries from £1,900 when fitted with its solar panels against from £3,995 on their own, and Octopus prices a Tesla Expansion Pack at £3,773 fitted with a new Powerwall 3 but £5,909 added later.
Do home batteries have VAT?
Installed batteries in homes are zero-rated for VAT until 31 March 2027, then 5%, under HMRC VAT Notice 708/6. That applies to batteries added to existing solar and to standalone batteries charged from the grid. Buying a battery without installation is charged at the standard rate.
Why is my quote higher than the median?
Common reasons are backup hardware, a consumer unit upgrade, a long cable run, fire-rated works to meet PAS 63100 indoors, three-phase equipment or a G99 network application. None is wrong in itself, but each should be itemised. A quote more than a fifth above the median with no explanation is worth challenging with a second quote.
What is the cheapest way to get a home battery?
Buy a size you can actually cycle, fit it at the same time as any solar, and get more than one written quote. In this site's model the first 10 kWh of storage earns most of the saving; capacity beyond what your home can empty each day adds cost faster than it adds savings.
Does a bigger battery cost less per kWh?
Yes. The official medians fall from £1,300 per kWh under 6 kWh to £630 per kWh above 11 kWh, because the installation labour and electrical work are shared across more capacity. That does not make a bigger battery better value if the extra capacity sits unused.
Why can a 13.5 kWh battery cost less in total than a 10 kWh one at the official medians?
Because DESNZ's median per kWh drops at the 11 kWh band edge: 10 kWh at £890 per kWh is £8,900, while 13.5 kWh at £630 per kWh is £8,505. The 11 kWh and over band's average installation was 15.5 kWh, so its median describes larger batteries than 13.5 kWh, and a published price for exactly 13.5 kWh should be tested with that in mind.
How much of a battery quote is the battery itself?
On the one comparison with public data, about 54% to 63%. Five UK retailers listed the Fox ESS EVO 10 at £2,880 to £3,356 before VAT on 7 October 2026, and Octopus's installed price for about 10 kWh is £5,336, so the remaining £1,980 to £2,456 pays for installation, commissioning, paperwork, warranty cover and margin. A supplier buying in volume pays less than a retail listing, so treat the split as indicative.
Are battery prices going up or down?
Mixed. DESNZ's median price per kWh rose 20% for batteries under 6 kWh between 2024/25 and 2025/26, fell 2% for 6 to 11 kWh and rose 7% for larger ones, while installations in the sample rose 80%. Batteries within each band also got slightly bigger, so the average installation cost a few per cent more even where the price per kWh barely moved.
Is it worth getting a battery for solar panels?
On the bill saving alone it takes a long time. In this site's model, for a London home with 4 kWp of solar on Octopus Flux, a 10 kWh battery at Octopus's £5,336 repays in about 13 years and a Powerwall 3 at £7,999 in about 14. On a flat tariff the same battery takes 25 years or more. It pays best with a time-of-use tariff, a size the home can cycle, and a price near the bottom of the range.