What has changed with Octopus home batteries?
Octopus Energy announced the Nook range on 22 June 2026 at its Energy Tech Summit. It has two products: the Nook Cube, a shoebox-sized plug-in battery aimed at renters and flat owners, and the Nook Colossus, a wall-mounted battery that an engineer installs for homeowners. Octopus calls itself the first major British energy supplier to sell its own home battery range.
The Cube holds 2kWh and, per Octopus, extra units can be added to reach 10.5kWh, all controlled through the Octopus app. The Colossus comes in 5kWh and 10kWh sizes and can be stacked up to 30kWh. Octopus lists a 12-year warranty and says both work with solar. Octopus has since said, in its October plug-in solar release, that the Cube is due in the first quarter of 2027.
| Detail | Nook Cube | Nook Colossus |
|---|---|---|
| Format | Plug-in, shoebox-sized | Wall-mounted, engineer-installed |
| Capacity | 2kWh, expandable to 10.5kWh | 5kWh or 10kWh, stackable to 30kWh |
| Aimed at | Renters and flats | Homeowners |
| Control | Octopus app | Not specified |
| Price | Not published | Not published |
| UK timing | Q1 2027 (Octopus, October 2026) | "From next year" |
Will the Octopus Nook Cube work with Home Assistant?
Octopus has not said so. Its announcement mentions only the Octopus app, and neither the press release nor trade coverage mentions a local API, Matter support or any third-party smart-home integration. Treat Home Assistant support as unconfirmed until the product ships and someone tests it.
If you want to see what a battery is doing regardless, the dependable route is metering the circuit yourself. Our Home Assistant energy monitoring guide and solar monitoring guide cover the clamps and plugs that work independently of any vendor app. Octopus customers who automate around tariff slots can also read our Octopus Agile cheapest-slots automation, because a battery's value depends on shifting use into cheap periods.
Is a plug-in battery legal in the UK?
That is the open question. The 2026 rules that legalised plug-in solar, covered in our plug-in solar panels UK explainer, are written around solar generation. Octopus says the Cube "simply plugs into a standard socket", but its announcement does not explain how a battery that can also discharge into your home circuits fits those rules, what its power output is, or what a landlord or insurer may require. We could find no published detail, so we are not guessing.
How much will the Nook battery cost?
Octopus has published no UK price for either product. It says only that batteries could help households save "hundreds of pounds a year" and that pairing them with its smart tariffs adds to the savings. For a sense of what batteries cost today, see our solar battery storage UK guide. A 2kWh battery is small: it covers a few hours of a typical evening, not a whole day, so the payback will hinge on the tariff gap between cheap and peak rates.
Should you wait for the Nook Cube?
If you rent, have no solar and want a low-effort way to shift usage onto a cheap overnight rate, waiting until Octopus publishes the price, output and legal position is reasonable, because the earliest date is early 2027. If you already own a home and have solar, an installed battery is available today, and waiting a year costs you savings. Either way, do not pay a deposit for anything marketed as a Nook before Octopus confirms the details itself.
