Tesla home energy products: Powerwall and Wall Connector

Tesla sells one home battery in the UK, the Powerwall 3, and one home charging product line, the Wall Connector. The Powerwall 3 is a 13.5 kWh unit with a built-in solar inverter, up to 11.04 kW of continuous output and a 10 year warranty with unlimited cycles¹. It works with or without solar panels, and can store grid electricity, so a household without a roof array can still buy one².

The commercial picture is less tidy than the specification. There is no single published UK price: independent guidance in May 2026 lists a Tesla Powerwall at £6,200 excluding installation³, while maker guidance in July 2026 puts a Powerwall 3 at around £6,700 to £7,600 per battery unit depending on installation requirements⁴. A rebate of £375 per Powerwall 3 or Powerwall 3 Expansion applies, claimable for up to two units per installation address, a maximum of £750⁵.

What the Powerwall does for independence is real but partial. It shifts when a home draws from the grid, and it keeps essential circuits running when the grid fails, but the household remains connected to a distribution network and, for grid charging, to a supplier. One measured case study found a Powerwall 3 system covering 56% of a home's electricity needs over a year⁶.

Tesla's home energy range: what a UK household can buy

The UK-facing range is narrow by comparison with the inverter and battery brands that fill the market. Tesla's home energy products sold here are the Powerwall 3 battery and the Wall Connector for electric vehicle charging. The Powerwall 2, which had been selling in the UK for over six years as of June 2024, is superseded by the Powerwall 3 and the two cannot be combined in the same system¹¹.

Tesla positions the Powerwall for UK homeowners with solar panels looking to store and use their own energy, for homes prone to power cuts, and for households aiming to cut electricity costs through peak rate optimisation¹². The suitability list is broader still: homes with or planning solar panels, those seeking lower bills, backup power during outages, control over energy use, or sustainability¹³.

Sizing guidance from a maker press release puts a 3 to 4 bedroom family home with typical daily use of 7 to 12 kWh in the 10 kWh to 13.5 kWh bracket, which is one Powerwall 3¹⁴. A large home or a home with an EV, at 10 to 20+ kWh of daily use, is placed in the 13.5 kWh to 20+ kWh bracket¹⁴. The Powerwall 3 is modular up to 94.5 kWh in total across seven units, and additional units and expansion packs can be mounted to the front of a Powerwall 3, stacked up to 216kWh².

For a household comparing this against the wider field, the home battery storage manufacturers page sets out the alternatives, and Tesla Powerwall vs Sigenergy SigenStor sets Powerwall against its closest all-in-one rival.

Powerwall 3: capacity, output and specifications

The headline figure is 13.5 kWh, and it is consistent across sources: the Powerwall 3 has a nominal capacity of 13.5 kWh per unit, and 13.5 kWh of usable storage⁸. The Powerwall 3 Expansion carries 13.5 kWh of usable battery energy⁷. The warranty describes the unit as having an energy capacity of 13.5 kWh on its initial installation date¹⁰.

Output is where the Powerwall 3 departs most sharply from its predecessor. Continuous power is 11.04 kW, against 5 kW for the Powerwall 2, and load start capacity is 185 A against 106 A¹¹. The Powerwall 2 datasheet gives real power maximum continuous of 3.68kW/5kW for charge and discharge¹⁶. One maker guidance page states peak power of up to 11.04 kW⁴; a maker product page describes 11kW of discharge capacity².

Mounting is flexible: internal or external, wall-mounted or floor-mounted¹⁷. The unit does not accept a generator connection¹⁷. The Powerwall 2 datasheet describes worldwide grid connection compatibility¹⁶.

Efficiency and round-trip losses in practice

Round-trip efficiency for the Powerwall 2 is stated as over 90%⁹. Maker guidance for the Powerwall 3 gives efficiency of up to 97%⁴. These are not the same measurement, and the difference matters: a round-trip figure accounts for energy lost on the way in and on the way out, while a headline efficiency figure may describe a narrower conversion stage. Neither figure is a guarantee of what a particular installation delivers, because losses depend on how the battery is cycled, the ambient temperature and the load profile.

The warranty sets a floor rather than a ceiling. It states 80% energy retention at 10 years following the initial installation date, expressed as a percentage of 13.5 kWh rated capacity, and specifies 37.8 MWh of aggregate throughput measured at the battery AC output¹⁰. Unlimited cycles are permitted within that term¹⁰.

What this means in practice is that a household should expect the battery to hold most, not all, of its capacity across a decade, and to lose a slice of every kilowatt hour that passes through it. The value case rests on the price difference between the electricity stored and the electricity displaced. One measured case study system delivered over £1,800 in total value in year one under a time-of-use configuration⁶. That is a single home's result, not a forecast, and it depends on the tariff and the household's pattern of use.

Buying direct from Tesla versus an independent installer

Tesla sells the Powerwall direct, and independent guidance lists it as available direct from Tesla³. Installation, however, runs through certified installers. All quotes include installation by Tesla-certified engineers, and the installer named on the product page is described as a Tesla certified installer¹. One UK installer, Good Energy, holds Tesla Powerwall Premium-Certified Installer status, a distinction held by just 3% of UK Tesla installers⁵.

The certification requirement is not only a manufacturer's preference. Installers under UK Government schemes must be TrustMark registered and/or Microgeneration Certification Scheme certified¹⁸. In Wales, Green Homes Wales requires installers to be registered with TrustMark as an approved PAS 2030 installer, or registered with TrustMark and certified with the Microgeneration Certification Scheme where the installation involves a low carbon technology such as a heat pump or solar panels¹⁹. Comparable self-certification schemes require registered installers to comply with detailed technical requirements, with installations subject to regular independent inspections and audits to ensure work complies with the Building Regulations²⁰. Independent guidance on solid wall insulation makes the same point in plainer terms: it should be fitted by a professional installer²¹.

For the wider question of how manufacturer installer networks work, the manufacturer installer networks page covers accredited schemes, and buying direct from manufacturers explains the routes.

Wall Connector: charging an EV from the same system

The Wall Connector is Tesla's home charging unit, and the Powerwall 3 lists EV charger support among its capabilities¹¹. The pairing is the point: a home with a Powerwall and an electric vehicle can charge the car from stored energy rather than from the grid at peak times, which is the same load-shifting logic that applies to any other appliance.

The wider charging context is favourable. The UK EV charging network has almost one charger for every EV²². That is a network figure, not a household one, and it says nothing about the cost of charging at home or the capacity of a particular supply.

Two practical constraints sit alongside the battery. The Powerwall 3 does not accept a generator connection¹⁷, so a petrol or diesel standby generator cannot be tied into the system. And the Powerwall warranty states plainly that the unit is not intended for use as a primary or backup power source for life-support systems, other medical equipment, or any other use where product failure could lead to injury to persons or loss of life or catastrophic property damage¹⁰. A household with a medical dependency on electricity should read that clause before treating a Powerwall as a substitute for a network supply.

What a Powerwall means for household energy independence

The independence a Powerwall delivers is temporal, not structural. It changes when a home draws from the grid and whether it draws at all during an outage, but the home remains connected to a distribution network and, for grid charging, to a supplier. The battery does not generate. It stores.

Backup is the clearest gain. If the grid goes down, the Powerwall instantly switches to stored energy, keeping essential appliances running¹². During a power cut a household can use up to 5kW of power at any one time, and a fully charged 13.5kWh Powerwall could last three or more days off-grid²³. One case study home reports that a full battery could last several days²⁴. Those figures assume a modest load; a home running heating, cooking and an EV will exhaust the same battery far sooner.

The measured limit is worth stating plainly. In a one-year case study, the system covered only 56% of the home's electricity needs⁶. That is a majority, but it is not independence, and it is one home's result under one configuration.

Control sits with the manufacturer's app. The Tesla Mobile App is the customer interface, and it provides real-time tracking of energy generated, stored and used, with insights and adjustable settings¹³. That is a dependence on a working internet connection, Tesla's servers and a supported app. The warranty makes the connection explicit: if the Powerwall is not connected to the internet for an extended period or has not been registered with Tesla, Tesla may not be able to honour the full ten year warranty, but will always honour the warranty for at least four years following first installation¹⁰.

The manufacturers and household energy independence page sets out how storage fits the wider picture, and firmware updates and product support life covers what happens to a battery when app support ends.

Warranty, registration and fault reporting

The Powerwall 3 carries a 10 year warranty with unlimited cycles¹⁷. Independent guidance lists the Powerwall at 13.5kWh with a 10 year term³, and the Powerwall 2 datasheet gives 10 years¹⁶. The warranty document, effective 27 January 2025, sets out the conditions¹⁰.

Registration and connection are conditions, not formalities. The warranty states that if the Powerwall is not connected to the internet for an extended period or has not been registered with Tesla, Tesla may not be able to honour the full ten year warranty, but will always honour the warranty for at least four years following the date the Powerwall was installed for the first time¹⁰.

A claim must include proof of the original purchase and any subsequent transfers of ownership, a description of the alleged defect, and the Powerwall's serial number and original installation date¹⁰. Before returning any product, an RMA number must be obtained from Tesla by submitting a Service Request Form¹⁰. Claims go to www.tesla.com/support/powerwall, by email to powerwallsupport@tesla.com, or by post to Burgemeester Stramanweg 122, 1101 EN, Amsterdam, Netherlands, marked for Powerwall Warranty Claims; the UK telephone number given is +44 800 098 8064¹⁰.

Tesla's general remedy is to repair the Powerwall using new or refurbished parts, replace it with an equivalent product new or refurbished, or refund the market price of an equivalent product at the time of the claim¹⁰. UK consumers who purchased directly from Tesla have additional rights: the right to reject the Powerwall and either obtain a full refund or request Tesla to repair it, with no refurbished parts permitted for that repair, and a further rejection right if Tesla fails to repair¹⁰. Nothing in the warranty limits or excludes Tesla's liability for death or personal injury resulting from negligence¹⁰.

For the general mechanics, see registering a warranty and keeping it valid and manufacturer warranties on home energy equipment.

SolarCity and how Tesla came to make home batteries

Tesla's entry into home energy did not begin with a battery. SolarCity was acquired by Tesla in an all-stock deal in the fourth quarter of 2016, which is how a car maker came to sit inside the residential solar business²⁵. The Powerwall line followed from that position: a battery sold to homes that were already generating their own electricity, and increasingly to homes that were not.

The product has moved with the market. The Powerwall 2 was AC-coupled and required a separate solar inverter⁹. The Powerwall 3 has a built-in solar inverter, more power output and better backup performance². That integration is the commercial logic: fewer boxes on the wall, less labour, and one manufacturer's app rather than two.

The UK context has shifted too. Solar Energy UK argues there is potential for producing transformers, inverters and other components domestically²⁶, and battery storage is credited in official guidance with maximising a household's use of solar generated electricity²⁷. Plug-in solar panels are compatible with UK domestic electrical systems and are already being developed for the UK market²⁸. None of that changes what a Powerwall is, but it explains why the category is growing around it.

For the wider field, the home battery storage manufacturers page covers the brands sold in the UK, and who owns which energy brand maps the parent groups.