Octopus Energy's published battery-only prices are £3,947 for a 5 kWh battery (a Fox ESS EVO 5 or an Enphase IQ Battery 5P), £5,336 for about 10 kWh (a Fox ESS EVO 10 or two Enphase units) and £7,999 for a 13.5 kWh Tesla Powerwall 3, installed, at April 2026 prices. All three sit below the official median price per kWh for their size. Octopus takes a £500 non-refundable deposit when you sign, and its Intelligent Octopus Flux tariff is currently open only to customers who bought solar panels and a battery from Octopus.
Octopus battery prices against the official medians
Octopus publishes one price for each battery-only installation. Dividing by the usable capacity makes them comparable with each other and with the official medians from DESNZ, which cover every MCS-certified battery fitted in an existing home between April 2025 and March 2026:
| What Octopus installs | Usable capacity | Octopus price | Per usable kWh | Official median per kWh for the size |
|---|---|---|---|---|
| One Enphase IQ Battery 5P | 5.0 kWh | £3,947 | about £789 | £1,300 (under 6 kWh) |
| Fox ESS EVO 10 | about 9.7 kWh | £5,336 | about £550 | £890 (6 to 11 kWh) |
| Two Enphase IQ Battery 5P | 10.0 kWh | £5,336 | about £534 | £890 |
| Tesla Powerwall 3 | 13.5 kWh | £7,999 | about £593 | £630 (11 kWh or more) |
| Powerwall 3 plus an Expansion Pack, same visit | 27 kWh | £11,772 | about £436 | £630 |
| An Expansion Pack added to an existing Powerwall 3 | 13.5 kWh more | £5,909 | about £438 | — |
Octopus prices are April 2026 prices from its battery-only and Expansion Pack pages. The Fox ESS EVO 5 is the other 5 kWh option at £3,947.
Every Octopus price is below the median for its size, and the gap is widest for 10 kWh, where two Enphase units cost about 40% less per usable kWh than the median. The pattern across sizes also holds: the price per kWh falls as the battery gets bigger, because the survey, labour and connection cost much the same for any size. Two other suppliers publish prices for the same Tesla unit, E.ON Next from £7,795 and EDF from £7,995, so Octopus’s Powerwall 3 price is in line rather than cheap.
The solar and battery packages
For homes buying panels at the same time, Octopus sells four packages. Its own descriptions:
| Package | Battery | Inverter | Panels | From | Warranty as Octopus states it |
|---|---|---|---|---|---|
| Smart | Fox ESS EP, 5.18 kWh | Fox ESS H1, 3.7 kW | 3 to 16 (455 W) | £7,915 with 4 panels and a battery | 12 years, inverter and battery |
| MAX Smart | Fox ESS EVO, 10.24 kWh | Built in, 5 kW | 3 to 12 (455 W) | Not listed separately | 12 years, inverter and battery |
| Optimised | One or two Enphase IQ Battery 5P | Enphase IQ microinverters | 4 to 30 (455 W) | £9,187 with 4 panels and a battery | 25 years microinverters, 15 years battery |
| FuturePower (Tesla) | Tesla Powerwall 3, 13.5 kWh | Built in | 10 to 30 (450 W) | £12,362 | 10 years, battery and built-in inverter |
Only the Tesla package offers whole-home backup in a power cut, and Octopus does not sell it for solar-only installs because the inverter is built into the battery. Two details on the page are worth a question when you get a quote. The Tesla package is priced “for 4 solar panels and a battery” but lists 10 to 30 panels. And the £11,115 price for the most popular system, 12 panels with a 10 kWh battery, is labelled April 2026 prices in one place and July 2026 in another. The solar panels and battery cost guide sets that price beside other suppliers’ and the official averages.
How buying from Octopus works
Octopus sets the process out on its battery-only page:
- You ask for a quote online, and Octopus contacts you to confirm the price.
- You complete a remote survey form. If you cannot, Octopus arranges a surveyor’s visit.
- Octopus takes a £500 advance payment, which it describes elsewhere on the same page as a non-refundable deposit taken when you sign the installation agreement.
- It books an installation date, and asks for the rest of the price once the installation is complete. A fixed-term loan is the alternative to paying in full.
If you already have solar panels that Octopus did not fit, it needs the MCS certificate for them and the specifications of your existing inverter for the network application. Feed-in Tariff customers may need to tell their FIT provider, and Octopus may ask for the last 12 months of generation. If you already have a battery from someone else, Octopus does not add to it; it refers you to one of its partner installers.
The deposit is modest. £500 on a £5,336 battery is about 9% of the price, against the 25% maximum the RECC consumer code allows its members. The terms that matter are that it is non-refundable once you sign and that the final price follows the survey.
The tariffs that come with it
Octopus’s case for its batteries rests on its tariffs, and the eligibility rules differ:
- Intelligent Octopus Flux lets Octopus control when the battery charges and exports. Its page says it needs solar panels and a compatible battery, lists compatible brands including Enphase, Fox ESS, GivEnergy, Huawei, Sigenergy and SolarEdge, and needs an export meter number (Octopus can apply for one). It also says the tariff is currently exclusive to customers who bought solar panels and a battery from Octopus, and on 7 October 2026 the page also marked it temporarily unavailable.
- Octopus Flux is open to other homes with solar panels and a home battery. In London on 28 October 2026 it charged 16.17p per kWh from 2am to 5am, 26.78p through the day and 37.38p from 4pm to 7pm, with no VAT since 1 October, and paid 30.31p per kWh for energy exported in that evening peak; Octopus raised its unit rates by about 10% on 19 October. The Octopus Flux rates page lists every region.
- Agile Octopus follows half-hourly wholesale prices and is the route Octopus suggests for battery-only homes without solar.
- The Charge Pack add-on pays at least £12 a month for letting Octopus use a supported battery in about two grid-balancing sessions a week, alongside Go, Intelligent Go, Flexible or fixed import tariffs with Outgoing Octopus.
Those London rates include the 5% VAT that applied in September. Household electricity carries no VAT from 1 October 2026 to 31 March 2027.
What each export tariff pays is in the five-tariff comparison, and for a battery installed without solar the no-solar battery guide tests Agile on 12 months of real prices.
What an Octopus battery saves
This site’s model, for a home using 3,000 kWh a year, with Octopus’s published battery prices:
| Battery and set-up (London) | Modelled saving a year | Simple payback |
|---|---|---|
| 5 kWh, 4 kWp solar, Octopus Flux | £174 | about 23 years |
| 10 kWh, 4 kWp solar, Octopus Flux | £414 | about 13 years |
| 13.5 kWh Powerwall 3, 4 kWp solar, Octopus Flux | £569 | about 14 years |
| 10 kWh, no solar, Agile Octopus | £335 | about 16 years |
Across Great Britain’s fourteen electricity regions, the 10 kWh battery on Flux saves between £379 (Yorkshire and South Scotland) and £455 (Merseyside and North Wales) in the same model. On these figures the 10 kWh battery is the best value of Octopus’s three sizes: the 5 kWh battery costs 74% as much and saves under half as much. Paybacks are before any fade in capacity, and Octopus’s own figure for a whole solar system, quoting the Energy Saving Trust, is 9 to 13 years. The calculator runs the model for your own usage and region.
What Octopus does not offer
The published range is narrow by design. Three battery brands, Fox ESS, Enphase and Tesla, cover every Octopus installation, so you will not be quoted Sunsynk, Sigenergy, myenergi or GivEnergy. Without Tesla, the largest size is about 10 kWh, and only the Tesla package gives whole-home backup. An independent installer can quote for those, or for a battery added to an existing battery, where Octopus refers you elsewhere.
That makes Octopus a useful reference rather than the only price to get. Put its price for your size next to a 10 kWh or 15 kWh quote from an MCS-certified installer, and check each against the official median. The Fox ESS, Enphase and Tesla Powerwall 3 pages cover the batteries Octopus fits in detail, and you can ask for battery storage quotes (we reply by email) to compare.
Backup is the clearest gap: only the Tesla package gives whole-home backup, and the backup power page lists what each system keeps on and what the extra hardware costs. Octopus does not quote a GivEnergy unit either, and the GivEnergy All in One page explains why that matters now.
Questions people ask
How much is an Octopus home battery?
Octopus publishes installed battery-only prices of £3,947 for a 5 kWh battery, £5,336 for a 10 kWh battery and £7,999 for a Tesla Powerwall 3 (13.5 kWh), at April 2026 prices. A Tesla Expansion Pack costs £3,773 fitted with a new Powerwall 3, or £5,909 added to an existing one. Its most popular solar and battery system, 12 panels with a 10 kWh battery, is £11,115.
Which batteries does Octopus install?
For battery installations Octopus offers the Fox ESS EVO in 5 kWh or 10.24 kWh, the Enphase IQ Battery 5P (one for 5 kWh, two for 10 kWh) and the Tesla Powerwall 3. Its entry solar package uses a Fox ESS EP 5.18 kWh battery with a Fox ESS H1 3.7 kW inverter. Octopus says installation is subject to network approval and it may offer an alternative product if one is unsuitable.
Can I get an Octopus battery without solar panels?
Yes. Octopus says it can install a stand-alone battery for most homes, and points battery-only homes without solar towards Agile Octopus, which charges the battery when prices are low. Its Flux tariffs need solar panels and a home battery.
Will Octopus add a battery to solar panels it did not install?
Yes, if you can provide the MCS certificate for the existing panels and the specifications of the existing inverter, which it needs for the network application. Feed-in Tariff customers may need to tell their FIT provider, and Octopus may ask for 12 months of generation data. If you already have a battery from another installer, Octopus refers you to a partner installer instead.
Can I join Intelligent Octopus Flux with a battery from another installer?
Not at the moment. Octopus's page says the tariff needs solar panels and a compatible battery that need not have been installed by Octopus, but that it is currently exclusive to customers who bought solar panels and a battery from Octopus. Standard Octopus Flux is open to other homes with solar panels, a home battery, a smart meter and an export meter number.
What warranty comes with an Octopus battery?
Octopus describes its Smart packages as backed by a 12-year warranty for the inverter and battery, its Enphase packages by 25 years on the microinverters and 15 years on the battery, and its Tesla package by 10 years on the battery and built-in inverter. Fox ESS's own UK policy gives EP batteries 10 years and EVO batteries 12, so on an EP battery ask in writing who stands behind years 11 and 12.