Octopus launches a plug-in home battery for renters
At its 2026 Energy Tech Summit on 22 June, Octopus introduced Nook, becoming the first major British supplier to sell its own home battery range. The headline product is a battery roughly the size of a shoebox that plugs into a standard wall socket, aimed at the renters and flat-dwellers who have been shut out of home storage. The pitch is storage without a fitted installation.
Two batteries, not one
Nook is a range with two units for two different homes:
| Unit | For | Capacity | Install |
|---|---|---|---|
| Nook Cube | Renters and flats | 2 kWh, stackable to 10.5 kWh | Plugs into a standard socket |
| Nook Colossus | Homeowners | 5 kWh, stackable to 30 kWh | Wall-mounted, fitted |
The Cube is the one that breaks the mould. A conventional home battery is a wall-mounted unit of 5 kWh or more, wired in by an electrician and tied to the property. The Cube plugs in like an appliance, so a renter can use it and take it with them when they move, and add more units later if they need the capacity.
How it works
Both units ship with Octopus Intelligence built in. Rather than setting timers, the battery works out when to charge cheap and when to discharge on its own, optimising against a smart tariff from the moment it is switched on. A plug-in unit like the Cube feeds power back into the home at around 800W, enough to cover background load and take the edge off the evening peak rather than run the whole house. Both units work with solar panels and carry a 12-year warranty.
The trade-off
At 2 kWh the Cube stores a fraction of what a fixed home battery holds, so it shifts a slice of daily usage rather than carrying a house through the evening. Its value rests on pairing it with a time-of-use tariff, where the gap between cheap overnight rates and expensive peak rates is what a battery turns into savings. With a flat tariff there is little for it to arbitrage. For a household weighing a full fitted battery instead, the battery calculator models the numbers, are home batteries worth it sets out where they pay off, and do I need a battery covers who benefits most.
Cost and payback
Octopus has not published a full price list. It says the Cube will pay for itself in two to three years even without solar panels, on the saving from charging cheap and using that power at peak, and that the wall-mounted Colossus will cost about a third less than the best-known battery brands. Those are Octopus's own figures and worth treating as a claim until independent reviews land, especially as a two-to-three-year payback is fast for home storage.
When you can get one
Both units arrive in 2027, sold to Octopus customers in the UK, Germany, Italy, Spain and France. The technical detail is still thin: there is no full spec sheet and no firm pricing yet, and a battery that pushes power back through a plug is a new category in the UK, so it is worth watching how the final specifications and approvals settle before 2027.
Why it matters
Home storage has been closed off to the third of UK households who rent, because a fixed battery needs an owner's permission and an electrician. A plug-in unit is the first mass-market attempt to open that up. If the payback claim holds, it turns a battery from a homeowner upgrade into something a tenant can buy off the shelf, which is a larger shift than the modest 2 kWh suggests. Octopus's wider ecosystem of apps and products is reflected in the technology score on its supplier profile, and you can compare every major supplier in the supplier rankings.