Tesla Powerwall 3 UK price, specs and warranty

What a Powerwall 3 costs in the UK

Tesla publishes UK list prices, but they are not what you pay: the page says they exclude VAT, delivery, installation and other costs, and that the final price comes from a Tesla Certified Installer. The installed prices below are the ones suppliers and installers publish.

Read against each other, Tesla’s list prices put the Backup Gateway 2 at £975 and one Expansion unit at £4,000. At £7,999 installed, a Powerwall 3 works out at about £593 per kWh, a little below the official median of £630 per kWh for MCS-certified batteries of 11 kWh or more fitted in 2025/26. Octopus’s pricing also shows why capacity is cheapest when it goes in on day one: the same Expansion Pack costs £3,773 at installation and £5,909 added later. Its Tesla solar package, the other batteries it fits and the deposit it takes are compared in our guide to Octopus’s home batteries.

Four published installed prices, £705 apart

Prices are from the suppliers’ own pages, read on 6 and 7 October 2026 (Octopus’s are April 2026 prices). The official median for MCS-certified batteries of 11 kWh or more fitted in 2025/26 was £630 per kWh, so Costco’s price sits on it and the other three about 6 to 8% below it.

The gap between cheapest and dearest is £705, about 9%, which is small enough that what is included matters more than the headline. Costco’s page says a grid application or connection offer may be charged to the customer and confirmed when the installation is booked, that the contract is with the installer rather than Costco, and that Costco’s returns policy does not apply to installed goods, though legal rights are unaffected. Octopus’s deposit is non-refundable once you sign. For solar and a Powerwall together, Octopus’s FuturePower package is listed from £12,362 and Good Energy lists 10 panels with a Powerwall 3 and power-cut protection from £13,900.

What the list price leaves out

• VAT. Installed batteries in homes are zero-rated until 31 March 2027 under HMRC’s VAT Notice 708/6, and the relief covers installation. A battery sold without installation carries the standard rate.
• The Gateway or Remote Meter. A non-backup Powerwall 3 needs a Tesla Remote Meter, which Tesla says is not included in the £5,000.
• Installation. Tesla says a typical Powerwall installation takes a full day, with the power off for about four to six hours, or eight or more if extra electrical work is needed.
• Network approval. Powerwall 3 can be set anywhere from 3.68 kW to 11.04 kW. Above the G98 limit of 16 A per phase, about 3.68 kW on a single-phase home counting every inverter, the installer must apply to the network under G99 before connecting.

The solar battery cost guide sets the four installed prices beside the official medians for every size and the average installation in each band.

Backup or no backup

The £975 difference in Tesla’s list prices is the choice between a battery that keeps the lights on and one that does not.

• With Backup Gateway 2, Powerwall 3 isolates the home from the grid in a cut and keeps it running, with Tesla’s Backup Reserve, Storm Watch and Go Off-Grid features.
• Without it, a Tesla Remote Meter takes the Gateway’s place and the battery gives no backup power. If solar panels are wired directly to the Powerwall, it keeps charging from them during a power cut but does not power the home.

A Gateway can be added later to upgrade a non-backup system. If backup matters to you, ask each installer to price it both ways. Our page on home battery backup explains what a backup circuit can and cannot run.

The specifications that matter in a UK home

Charging speed against the cheap window. Powerwall 3 charges at up to 5 kW on its own, so filling 13.5 kWh from empty takes roughly 2 hours 45 minutes before losses. That fits inside the three-hour cheap window on Octopus Flux (2am to 5am). With one Expansion unit, 27 kWh at up to 8 kW takes about 3 hours 20 minutes, slightly longer than the window.

A solar inverter built in. Powerwall 3 has three solar inputs and accepts up to 20 kW of panels, so a new solar and battery system needs no separate solar inverter. Tesla positions it for new solar-plus-storage installations, though it says Powerwall 3 can also be added to existing solar and works with all major inverter brands. See AC vs DC coupled batteries for what that choice means.

Weight and where it can go. At 130 kg it needs a solid floor or wall, and Tesla limits the bottom of a wall-mounted unit to 1,140 mm off the ground. It is rated IP55 for outdoor use, which matters because PAS 63100, the fire-safety specification for batteries in homes, prefers outdoor locations and rules out bedrooms, escape routes and lofts. See PAS 63100 explained.

The largest system is larger than a home may hold. Tesla’s datasheet allows up to four Powerwall 3 units and three Expansion units, 94.5 kWh. For homes within its scope, PAS 63100 caps total storage at 80 kWh outdoors, in a garage or in an outbuilding, and 40 kWh elsewhere, so the top configuration goes beyond what the specification allows in a single dwelling.

The warranty in plain English

The UK warranty (Rev. 1.16, effective 3 December 2025) is given by Tesla Motors Netherlands B.V. and runs for 10 years from installation, with 80% of the 13.5 kWh retained at year 10. The conditions matter more than the headline:

• Unlimited cycles, for three uses. Solar self-consumption, time-based control (storing grid or solar energy for time-of-use shifting) and backup have no throughput limit. Other uses, such as trading or grid services, or any mix that includes them, are capped at 37.8 MWh, about 2,800 full cycles.
• Bought and installed the right way. Cover applies only to units bought from Tesla or a certified installer in the European warranty region and installed there. Faults from installation, modification or repair by anyone else are excluded, as is moving the unit to another address without Tesla’s written consent.
• Kept online. If the Powerwall is offline for long periods or not registered, Tesla may not honour the full 10 years, but it will always honour at least 4.
• Transferable. A later owner can claim with proof of ownership. For a UK house sale, Tesla asks for a copy of the Transfer Deed and photos of the stickers on the Gateway or Remote Meter and every Powerwall.
• Claims go through the installer. Tesla chooses whether to repair, replace or refund the market price, and you start a claim with the certified installer who sold the system.

What a Powerwall 3 saves and how long it takes to pay back

In this site’s model, a home using 3,000 kWh a year with 4 kWp of solar on Octopus Flux saves between £511 a year (South Scotland) and £623 (Merseyside and North Wales) with a 13.5 kWh battery, and £569 in London. Against Octopus’s £7,999 that is a simple payback of 12.8 to 15.7 years, 14.1 in London. At the official median of about £8,505 for 13.5 kWh it is 13.7 to 16.7 years. Both ignore the battery losing capacity over time. The model counts only the battery’s bill saving: it puts no value on the built-in solar inverter or on backup in a power cut, which are the reasons many buyers pay for a Powerwall. The saving for every one of the 14 electricity regions is in our article on Powerwall 3 payback by region.

Is a second Powerwall worth it?

A second unit takes the system to 27 kWh and adds less than the first, because a typical home cannot empty it every day:

The two prices are Octopus’s, for an Expansion Pack fitted with a new Powerwall 3 and for one added to an existing unit later. An average home gains little from the second unit, which is the case for fitting a single battery of the right size instead; a home with a heat pump or an electric car is the exception. Ask for the price both ways before you decide, because adding capacity later costs more.

Tariffs for a Powerwall

The Tesla Energy Plan tariff has been retired in the UK, and Octopus names Flux as its successor. Octopus Flux needs solar panels, a home battery, a smart meter, an export MPAN and the MCS certificate, and its rates for every region are on the Octopus Flux rates page. Intelligent Octopus Flux can control a Powerwall directly, with the reserve fixed at 20%, but Octopus currently limits it to customers who bought solar panels and a battery from Octopus. Without solar, an overnight tariff or Agile Octopus is the usual route; see the best tariff for a home battery.

Who a Powerwall 3 suits

It suits homes fitting new solar and a battery together, homes with high evening use, an electric car or a heat pump, and anyone who wants whole-home backup. In this site’s model, a London home using 3,000 kWh a year with 4 kWp of solar on Flux saves about £569 a year with 13.5 kWh against £414 with 10 kWh, so the extra capacity pays only if the home can use it. For a smaller home, a 5 or 10 kWh battery may capture most of the saving for less; see 13.5kWh batteries and the calculator.

How long a full battery lasts at each load, from 250 W to the 11.04 kW maximum, is in how long a 13.5kWh battery lasts.

How to check a Powerwall 3 quote

1. Confirm the installer is certified. Tesla’s UK Certified Installer finder lists them by postcode, and some carry a Premium Installer badge.
2. Ask whether the Gateway is included, or whether it is a non-backup system with a Remote Meter.
3. Ask for the output setting and the network route: G98 notification or a G99 application, and any export limit.
4. Check the location against PAS 63100 and ask for the statement of conformity with the electrical certificate.
5. Price any Expansion unit now if you think you will want one; later it may cost more.

Then compare two or three battery storage quotes line by line, including one for a different brand. The Fox ESS and Enphase pages cover the most common alternatives Octopus and other large installers offer.