Battery storage — South West London
Tesla Powerwall in South West London
What Tesla Powerwall means for a South West London home, how it compares with the systems we fit, and a written answer on supply, installation and warranty if it is the one you want.
South-west London is where a Tesla Powerwall 3 most often meets a terrace or a flat. Terraced homes are the largest single type in Merton, at 35.7% of households, and purpose-built flats are 31.3% of Sutton’s and 29.8% of Kingston’s (Census 2021), so the first question is usually where a 130 kg unit can go and who has to agree. This page answers that, then covers the two UK Power Networks areas that split the patch and the boroughs’ own figures. For roofs, see solar panels in south-west London; for storage generally, our battery storage guide; and for local detail, battery storage in Wimbledon, Kingston and Sutton.
The battery system in HCE’s own job photos is EnSmart; if Tesla Powerwall is what you want, ask us and we will confirm in writing how it would be supplied, who installs and commissions it, and what warranty attaches. Tesla makes that the deciding point: its warranty covers a Powerwall “purchased from Tesla or a Tesla certified installer”, and installation or commissioning by anyone else is one of the grounds on which cover may be voided. Check any company quoting you, HCE included, in Tesla’s certified-installer finder.
Quick answer
Tesla Powerwall in South West London:
- Our own work: the battery systems in HCE's own job photos are EnSmart; if Tesla Powerwall is what you want, ask us and we will confirm in writing how it would be supplied, who installs and commissions it, and what warranty attaches.
- Cost: the Energy Saving Trust puts home battery storage at £1,500 to £10,000, with a 5 kWh system at around £4,600; a quote for your home comes from a survey of your usage.
- VAT: residential battery installations carry 0% VAT until 31 March 2027, then 5% from 1 April 2027.
- Grid: every battery is notified to, or approved by, the local network operator depending on its size (G98 or G99); the installer handles it.
- Power cuts: a standard grid-tied battery shuts down when the grid does; backup has to be designed in and is never assumed.
- Who fits it: HCE is a NAPIT member (73495), MCS-certified for solar PV and battery storage via NAPIT, and a HIES Consumer Code member.
Figures: Energy Saving Trust (batteries, updated 19 August 2026) · HMRC VAT Notice 708/6. Product facts are the manufacturer's, cited below.
How a home battery gets fitted in South West London
Four steps from first call to switch-on. No pressure at any stage, and a straight answer if it would not pay its way.
- Step 1
Your usage, not a guess
We look at when your South West London home uses power, especially evenings, and your tariff, because that, not the sunniest month, decides the battery size.
- Step 2
Sizing and siting
Where the unit can go (garage, utility room or an outside wall, as the manufacturer allows), whether it pairs with existing panels, and a written, itemised quote.
- Step 3
Installation and notification
Fitting and commissioning, with the battery notified to or approved by your network operator depending on its size. Backup in a power cut only if it is designed in.
- Step 4
Settings and handover
Charge and discharge set up around your tariff, the app explained, and the warranty documents in your hand.
How Tesla Powerwall fits South West London homes
A Powerwall 3 is 1105 × 609 × 193 mm and weighs 130 kg, and it can stand on the floor or hang on a wall. In a Merton or Richmond mid-terrace with no side access, that means two people carrying it through the house to a rear wall, which its IP55 enclosure and −20°C to 50°C range allow, or an indoor spot off the escape route near the consumer unit; hallways are best kept clear. The semis of Kingston (31.7% of the borough’s households) and Sutton (27.9%) more often have a garage or side wall. Much of Richmond and Wimbledon is conservation area, so keep any outdoor unit off the street-facing elevation and check with the council first.
Flats change the order of decisions. A converted flat in a Wimbledon or Twickenham house usually has its own supply and meter, so a Powerwall would serve that flat alone and needs the freeholder’s consent, and UK Power Networks says the building owner’s permission is needed before solar or storage work starts on any multi-occupied building. On the grid side the patch splits: the town centres of Wimbledon, Mitcham and Tooting are in London Power Networks, while Kingston, Surbiton, Twickenham, Richmond, Sutton, Carshalton and Croydon are in South Eastern Power Networks, several within 1.5 km of a boundary, so check your postcode. Either way, a Powerwall set at 3.68 kW or below is notified under G98, and a higher setting needs G99 approval before work.
South West London: sunshine, the grid and local uptake
PVGIS gives a 4 kWp south-facing array in the ten towns we cover between about 137 kWh (Surbiton and Croydon) and 140 kWh (Wimbledon) in December, and between about 479 kWh (Mitcham, Tooting and Richmond) and 484 kWh (Surbiton) in June: about 4.4 to 4.5 kWh a day against 16.0 to 16.1 kWh (our arithmetic). On a terrace roof smaller than 4 kWp the figures scale down, which makes the case for sizing any battery to the evening use you actually have.
DESNZ records 16,866 solar PV installations across Croydon, Sutton, Richmond, Merton, Wandsworth and Kingston at the end of 2025 (our sum), Croydon the largest at 5,161. DVLA counts 38,041 privately kept plug-in vehicles across the same six boroughs at the end of June 2026, up from 31,196 a year earlier (our sum). Ofgem’s 2024/25 figures show about 11.2 supply interruptions per 100 customers and 10.5 minutes lost per customer for London Power Networks, and 42.2 and 30.4 for South Eastern Power Networks. A Powerwall keeps the home supplied in an outage only when a Backup Gateway 2 is installed.
Local facts, sourced
Tesla Powerwall and South West London in numbers
Every figure below comes from a named public or manufacturer source.
-
Merton: 35.7% of 81,726 households in terraced homes, 19.0% semi-detached, 5.7% detached, 28.4% in purpose-built flats and 9.2% in converted houses.
Source: ONS Census 2021, TS044 via Nomis (Merton)
-
Kingston upon Thames: 31.7% semi-detached, 17.2% terraced, 12.6% detached and 29.8% purpose-built flats; 27.3% of households rent privately.
Source: ONS Census 2021, TS044 and TS054 via Nomis (Kingston upon Thames)
-
Sutton: 31.3% purpose-built flats, 27.9% semi-detached, 24.5% terraced and 10.5% detached.
Source: ONS Census 2021, TS044 via Nomis (Sutton)
-
PVGIS: about 137–140 kWh in December and 479–484 kWh in June for a 4 kWp south-facing array across the ten south-west London towns we cover.
Source: PVGIS 5.3, European Commission Joint Research Centre (PVGIS-SARAH3 2005–2023), 4 kWp, 35°, due south, 14% losses, building-mounted, runs of 15 October 2026 (batteryStats.ts); daily figures and ranges are our arithmetic
-
DESNZ: 5,161 solar PV installations across Croydon (21.67 MW), 2,690 across Sutton and 2,608 across Richmond upon Thames, end of 2025.
Source: DESNZ, Renewable electricity by local authority 2014 to 2025, Solar PV sites and capacity (published 29 September 2026; end-of-2025 figures as first published, installations of every size)
-
Privately kept plug-in vehicles: 9,010 across Croydon (from 7,049) and 6,425 across Richmond upon Thames (from 5,499), June 2026 against June 2025.
Source: DfT and DVLA, VEH0142 licensed plug-in vehicles by local authority, privately kept, 2026 Q2 against 2025 Q2 (published 23 September 2026)
-
Wimbledon, Mitcham and Tooting town centres are in London Power Networks; Kingston, Surbiton, Twickenham, Richmond, Sutton, Carshalton and Croydon are in South Eastern Power Networks.
Source: UK Power Networks licence boundaries (December 2024) and NESO GB DNO licence areas (May 2024), town-centre points
-
Ofgem 2024/25: London Power Networks about 11.2 interruptions per 100 customers and 10.5 minutes lost; South Eastern Power Networks 42.2 and 30.4.
Source: Ofgem, RIIO-2 Electricity Distribution annual report 2024 to 2025, supplementary datafile, CI and CML planned and unplanned (published 15 January 2026; severe-weather adjustments applied from DNO submissions)
-
UK Power Networks says the building owner’s permission is needed before solar or storage work begins on a multi-occupied building such as a block of flats.
Source: UK Power Networks, Solar and storage: cost, time and what’s involved (read 15 October 2026)
Data last reviewed: October 2026
Battery storage across South West London
Town by town, with each town's own sunshine figures and network operator: battery storage in Kingston upon Thames, battery storage in Wimbledon, battery storage in Surbiton, battery storage in Twickenham, battery storage in Sutton, battery storage in Richmond, battery storage in Croydon, battery storage in Mitcham, battery storage in Carshalton and battery storage in Tooting.
The full specification is on our Tesla Powerwall page. For how sizing, warranties and pairing with panels work, see our main battery storage guide, and for the wider area, solar panels across South West London. For a longer read, see Smaller homes in South West London: five batteries compared.
Comparing systems for a South West London home? See EnSmart in South West London, Sigenergy in South West London, EcoFlow PowerOcean in South West London and Fox ESS in South West London.
Tesla Powerwall in South West London: questions
Can a Powerwall 3 go in a converted flat in Wimbledon or Twickenham?
Sometimes. The flat needs its own space for a 130 kg unit, usually a rear wall or a ground-floor room, and the freeholder’s consent, and UK Power Networks needs the building owner’s permission for work on a multi-occupied building. If you rent, the landlord decides first. If there is no suitable space that is legally yours, we will say so.
Is a south-west London terrace too small for a Powerwall?
Not physically: the unit is 193 mm deep and can go on a rear wall or the floor of a utility space. The question is whether 13.5 kWh suits your use. A smaller terrace roof and modest evening use can mean a smaller modular battery pays back faster, so both should be modelled against your own consumption.
Am I on London Power Networks or South Eastern Power Networks?
It depends on the street. Wimbledon, Mitcham and Tooting town centres are on London Power Networks; Kingston, Surbiton, Twickenham, Richmond, Sutton, Carshalton and Croydon on South Eastern Power Networks, and several sit close to a boundary. The Energy Networks Association’s postcode tool gives your operator. Both are UK Power Networks, and the installer handles the G98 or G99 paperwork.