Battery storage — Sussex
Tesla Powerwall in Sussex
What Tesla Powerwall means for a Sussex 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.
Our Sussex pages cover three towns with very different houses, and that difference decides where a Tesla Powerwall 3 can go. Horsham district is house-led, with 37.2% of households in detached homes; Crawley is a terrace town, with 37.4% of its 45,500 households in terraced houses; and in Haywards Heath purpose-built flats make up 27.3% of homes (Census 2021). This page sets the Powerwall’s size, weight and ratings against that mix, explains the UK Power Networks paperwork that applies across all three, and adds the local solar and plug-in car figures. Read solar panels in Sussex for the roofs, our battery storage guide for how storage works, and the town pages for battery storage in Horsham, Crawley and Haywards Heath.
The battery system in HCE’s own job photos is EnSmart; if a 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. With Tesla that answer decides the warranty itself. Tesla limits it to a Powerwall “purchased from Tesla or a Tesla certified installer”, and lists installation, commissioning or repair by anyone else among the grounds on which cover may be voided. Whoever quotes you in Sussex, check them in Tesla’s certified-installer finder and get the supply route in writing.
Quick answer
Tesla Powerwall in Sussex:
- 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 Sussex
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 Sussex 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 Sussex homes
In Crawley’s planned neighbourhoods a semi or end-terrace usually has side access or an attached garage, so a Powerwall can go on the side wall near the meter or stand in the garage. A mid-terrace in Broadfield or Ifield often has neither, and the unit, 130 kg and 1105 × 609 × 193 mm, has to be carried through the house by two people to a rear wall. Its IP55 enclosure, with IP67 on the battery and power electronics, and its −20°C to 50°C operating range make a rear outside wall a workable position, provided the cable route back to the consumer unit is sensible. In Horsham’s detached and semi-detached suburbs, Roffey and Holbrook among them, a garage or utility room is the usual answer. In the historic core around the Causeway, a conservation area, keep any outdoor unit to a rear or side elevation and speak to Horsham District Council first if the house is listed.
The flats are where a Powerwall is least likely to work. Haywards Heath has 3,600 purpose-built apartments, and a battery there needs the freeholder’s or management company’s agreement and somewhere it can legally and safely sit, which is not always available. All three town centres sit in UK Power Networks’ South Eastern Power Networks area, Horsham’s about 2.9 km from SSEN’s boundary. The Powerwall’s output is set between 3.68 kW and 11.04 kW: at 3.68 kW or below the installer notifies under G98 within 28 days, above that a G99 approval comes first. UK Power Networks says it automatically approves an application where the maximum export after any export limitation is under 5 kW, so a design that limits export below that line usually moves faster than one asking for the full output.
Sussex: sunshine, the grid and local uptake
The three Sussex towns run fairly close on winter sun and further apart in summer. PVGIS gives a 4 kWp south-facing array about 139 kWh in December in Crawley, 140 kWh in Horsham and 146 kWh in Haywards Heath, and between about 493 kWh (Crawley) and 526 kWh (Haywards Heath) in June: about 4.5 to 4.7 kWh a day in December against 16.4 to 17.5 kWh in June (our arithmetic). A Powerwall’s 13.5 kWh is a summer-evening battery here, not a winter one.
DESNZ records 5,845 solar PV installations across Mid Sussex, 4,976 across Horsham district and 2,264 across Crawley at the end of 2025, 13,085 in all (our sum). DVLA counts 5,430 privately kept plug-in vehicles in Mid Sussex, 5,228 in Horsham district and 2,310 in Crawley at the end of June 2026, up from 9,570 to 12,968 across the three in a year (our sums). Ofgem’s 2024/25 figures for South Eastern Power Networks show about 42.2 supply interruptions per 100 customers and 30.4 minutes lost per customer, against 39.7 and 35.1 for all GB licence areas; a Powerwall supplies the home in an outage only when a Backup Gateway 2 is installed.
Local facts, sourced
Tesla Powerwall and Sussex in numbers
Every figure below comes from a named public or manufacturer source.
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Crawley at the 2021 Census: 45,500 households, 37.4% in terraced houses, 22.7% semi-detached, 14.2% detached and 25.1% in flats or maisonettes; 22.9% rent from a social landlord.
Source: ONS Census 2021, TS044 and TS054 (Crawley), as cited in RUN11-CLAIMS-TABLE-2026-10-14.md
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Horsham district: 37.2% of its 62,371 households live in detached homes, 26.9% in semis and 17.1% in terraces, and 72.3% own their home.
Source: ONS Census 2021, TS044 and TS054 via Nomis (Horsham)
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Haywards Heath has 3,600 purpose-built flats, 27.3% of its 13,216 households, alongside 25.4% detached and 26.9% semi-detached homes.
Source: ONS Census 2021, TS044 via Nomis (Haywards Heath wards)
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PVGIS: about 139–146 kWh in December and 493–526 kWh in June for a 4 kWp south-facing array across Horsham, Crawley and Haywards Heath.
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
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DESNZ: 5,845 solar PV installations across Mid Sussex (40.28 MW), 4,976 across Horsham district (72.67 MW) and 2,264 across Crawley (11.06 MW), 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)
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Privately kept plug-in vehicles: 5,430 in Mid Sussex (from 4,027), 5,228 in Horsham district (from 3,924) and 2,310 in Crawley (from 1,619), 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)
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The town centres of Horsham, Crawley and Haywards Heath all sit in UK Power Networks’ South Eastern Power Networks licence area.
Source: UK Power Networks licence boundaries (December 2024) and NESO GB DNO licence areas (May 2024), town-centre points
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UK Power Networks automatically approves an application where the maximum export after any export limitation scheme is under 5 kW.
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 Sussex
Town by town, with each town's own sunshine figures and network operator: battery storage in Horsham, battery storage in Crawley and battery storage in Haywards Heath.
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 Sussex. For a longer read, see Sussex home batteries: where each of five brands can go.
Comparing systems for a Sussex home? See EnSmart in Sussex, Sigenergy in Sussex, EcoFlow PowerOcean in Sussex and Fox ESS in Sussex.
Tesla Powerwall in Sussex: questions
Can a Powerwall 3 go on the back wall of a Crawley terrace?
Often, yes. It is rated IP55 overall, with IP67 on the battery and power electronics, and operates from −20°C to 50°C, so a rear outside wall is a recognised position. The practical issues are getting a 130 kg unit through a mid-terrace house, which takes two people, and the length of the cable run back to the consumer unit, which the survey prices. If you rent from the council or a housing association, the landlord has to agree first.
Is a 13.5 kWh Powerwall too big for a smaller Sussex home?
It can be. A Powerwall 3 comes in one size, so you cannot buy half of one. If your evening use is modest, a smaller modular battery may pay back faster, and both options should be modelled against your own consumption data before either is recommended. Tesla’s Expansion units only add capacity, so they help large homes rather than small ones.
How does UK Power Networks treat a Powerwall in Horsham, Crawley or Haywards Heath?
All three town centres are on its South Eastern network. At an output of 3.68 kW or less the installer notifies UK Power Networks within 28 days under G98. Above that a G99 application is approved before work starts, and UK Power Networks says it approves automatically where the maximum export after any export limitation is under 5 kW. Your installer handles the forms, and there is nothing to pay UK Power Networks unless your supply needs upgrading.