Two questions decide most Powerwall conversations: what it costs, and what the warranty is worth. Both have published answers, and both are routinely reported wrongly — including the widely repeated line that Tesla does not publish a UK price. It does. Here is what its own documents say, read on 25 September 2026, with the parts that matter to a buyer rather than a brochure.
What Tesla publishes on price
Tesla’s UK Powerwall marketing page carries no price at all; its only call to action is a quote request. One step deeper, on the quote page, the figures appear:
| What | Price (Tesla’s own page) |
|---|---|
| 1 Powerwall 3, without Gateway | £5,000* |
| 1 Powerwall 3, with Gateway | £5,975* |
| 1 Powerwall 3 + 1 Expansion, without Gateway | £9,000* |
| 1 Powerwall 3 + 1 Expansion, with Gateway | £9,975* |
*Tesla marks these as excluding VAT, delivery and installation. The line without a Gateway also needs a Tesla Remote Meter, which is not in the price.
For an installed figure from a named company rather than a range, Octopus Energy publishes £7,999 for a 13.5 kWh Powerwall 3, and £3,773 for an Expansion fitted at the same time (£5,909 if added later), on a page that states its costs are based on April 2026 prices. We quote those two sources instead of the “£8,500 to £12,000 installed” bands that circulate, because those bands are aggregates of other people’s jobs with no stated basis and no date.
The route to buying is worth knowing too: Tesla does not sell Powerwall through a UK checkout. You submit a quote request and a Tesla Certified Installer contacts you — which is the same certification thread that runs through the warranty.
The warranty condition most pages leave out
The governing document is the Tesla Powerwall Warranty (European Warranty Region), revision 1.16, effective 3 December 2025. The headline terms are good, and they are widely quoted: ten years, 13.5 kWh at installation, 80% of that capacity retained at ten years for UK installations, a transferable warranty, claims through Tesla Motors Netherlands B.V.
What is almost never quoted is the first sentence of the scope. The warranty applies to a Powerwall that “was purchased from Tesla or a Tesla certified installer in the European Warranty Region”. And among the grounds on which cover “may result in your Warranty being voided”, the document lists storage, installation, commissioning or repair “performed by anyone other than Tesla or a Tesla certified installer”. Tesla closes the loop itself: “Please contact Tesla if you have any concerns regarding whether you purchased your Powerwall from a Tesla certified installer.”
So the ten years is not a property of the hardware. It is a property of the supply chain the hardware arrived through. If the warranty is a significant part of why you want a Powerwall — and for many people it is the whole reason — then the question to ask any company quoting you, us included, is simple: how is the unit supplied, and what warranty attaches to it? Ask for the answer in writing, and check your postcode against Tesla’s own certified-installer finder.
Two smaller details in the same document. “Unlimited cycles” applies to solar self-consumption, time-based control and backup; any other application, or a combination Tesla does not list, is capped at 37.8 MWh of aggregate throughput. And the enhanced UK consumer rights in the document’s United Kingdom appendix — the 30-day rejection right, no refurbished parts on repair — are written for consumers who bought directly from Tesla, not through an installer.
Backup: the other thing that moves the price
A Powerwall 3 keeps your home running in a power cut only if it is installed in a backup configuration, which means a Backup Gateway 2. Tesla is explicit that in the cheaper non-backup arrangement, using a Tesla Remote Meter instead, the system “will not provide backup power” during an outage. That single decision explains most of the gap between two otherwise identical Powerwall quotes, and it is the one to settle before comparing prices.
Retrofits have a related catch: where existing panels run through a third-party inverter, that solar will not necessarily keep generating into a backed-up home unless the design allows for it.
The numbers behind the sales lines
Worth having in your head when you read anyone’s Powerwall page, ours included:
- 13.5 kWh usable, quoted by Tesla as a beginning-of-life minimum at 25°C and 5 kW.
- Output configurable from 3.68 kW to 11.04 kW at 230 V. That is not trivia: 3.68 kW per phase is the threshold below which a connection is notified to the network operator after the event under G98; above it, a G99 application is approved first.
- Two efficiency figures, not one: 97.5% solar to home or grid, and 89% solar → battery → home or grid. Tesla publishes no figure labelled “round-trip efficiency”, so any page quoting one is estimating.
- Maximum system: four Powerwall 3 units plus three Expansions — seven units, 44 kW, 94.5 kWh. The marketing page reads as though the ceiling is higher; the datasheet is what to design from.
- 1105 × 609 × 193 mm and 130 kg, IP55 enclosure with IP67 ingress on the battery and power electronics, rated −20°C to 50°C, under 50 dB(A) typical at one metre.
Our Tesla Powerwall 3 page sets all of this out alongside how we design and install one, the solar battery storage hub compares it with the other ranges we fit, and the solar battery storage cost page covers what sits inside an installed price whichever battery you choose.
Sources: Tesla, Powerwall Warranty (European Warranty Region) Rev. 1.16, effective 3 December 2025; Tesla, Powerwall 3 UK datasheet (2026); tesla.com/en_gb/powerwall and /powerwall/get; Tesla, Powerwall non-backup configuration support page; Octopus Energy, battery storage pricing (stated April 2026 basis); Energy Networks Association, EREC G98 and G99; HMRC VAT Notice 708/6. All read 25 September 2026.