Surrey’s houses are larger than the national pattern. At the 2021 Census 32.2% of the county’s households lived in detached houses and a further 29.2% in semis, against 22.9% detached across England; in Surrey Heath the detached share reaches 43.7%, and in Waverley 40.4%. So the first battery question in a Surrey home is rarely whether there is room. It is how much storage the household will really use. This guide sets five brands side by side on that question, using only what each manufacturer publishes: EnSmart batteries in Surrey, the Tesla Powerwall in Surrey, Sigenergy SigenStor, EcoFlow PowerOcean and Fox ESS.
One fact shapes everything below. The battery systems in HCE’s own job photos are EnSmart, and EnSmart is the range we fit. For any of the other four, ask us and we will confirm in writing how it would be supplied, who installs and commissions it, and what warranty attaches. There is no ranking here and no price per brand. For the county’s roofs, see solar panels in Surrey; for how storage works whatever the brand, our battery storage guide.
How each brand sells capacity
| Brand | Smallest published step | How it grows |
|---|---|---|
| EnSmart SolarAll | 5.12 kWh ELV-W wall pack | 5.12 or 10.24 kWh wall packs; 15 or 20 kWh ELV-F floor packs |
| Tesla Powerwall 3 | 13.5 kWh unit | Expansion units of 13.5 kWh; datasheet ceiling of 4 Powerwalls plus 3 Expansions, 94.5 kWh |
| Sigenergy SigenStor | 6.02 kWh module | 6.02 or 9.04 kWh modules, one to six per controller |
| EcoFlow PowerOcean | 5 kWh pack | 5 kWh steps, up to 20 kWh on one single-phase inverter |
| Fox ESS | 5.18 kWh EP5 | Four EP5s to a quoted 20.8 kWh; EP11 units of 10.36 kWh to 41.6 kWh |
In a Surrey house those ceilings matter less than they look. PVGIS puts a 4 kWp south-facing array across the 22 Surrey towns we cover at about 130 kWh in December (Guildford) to 140 kWh (Cranleigh and Dorking), and about 479 kWh (Camberley) to 501 kWh in June (Cranleigh). Godalming is the exception in December: its town-centre point sits in the Wey valley, where PVGIS’s terrain horizon cuts it to about 74 kWh; homes on higher ground or with an open southern view do better. Elsewhere, on our arithmetic, that is roughly 4.2 to 4.5 kWh a day in December and 16.0 to 16.7 kWh in June. A December day fits inside every brand’s smallest step; an average June day is more than one Powerwall 3 holds. So a battery is sized to the evening load, and winter charging is a tariff decision.
Two networks, five inverter line-ups
Surrey sits on two network operators. The town centres of Guildford, Epsom, Reigate, Dorking and Redhill are in UK Power Networks’ South Eastern Power Networks area; Farnham, Camberley, Haslemere and Egham are in SSEN’s Southern Electric Power Distribution area, and Godalming, Staines-upon-Thames and Virginia Water sit within 2 km of the line. The Energy Networks Association’s postcode tool settles your address. On both, up to 16 A per phase (3.68 kW) is a G98 notification after commissioning, and anything larger needs G99 approval first. Each brand’s inverter decides the route:
- EnSmart publishes the single-phase SolarAll-H at 3–6 kW, so the size chosen decides the route; we check the ENA type-test register entry for the exact model first.
- Tesla lists Powerwall 3 output settings from 3.68 kW to 11.04 kW; set at 3.68 kW, it is a notification.
- Sigenergy’s 3.6 kW single-phase controller is rated at 16.0 A, on the G98 line; the 4.0 kW model is 18.2 A and a G99 application.
- EcoFlow publishes 6 kW of continuous off-grid output for a single-phase PowerOcean, above the line, so ask how the connection would be applied for and whether export limitation is in the design.
- Fox ESS makes the H1-G2 from 3.0 to 6.0 kW and lists the 3.7 kW model at 3,680 VA for G98.
A larger Surrey house with a three-phase supply has more headroom, since G98 then covers up to 11.04 kW across three phases. Whether the supply is three-phase is a survey check, not something to read from the size of the house.
Where each one lives in a Surrey house
The integral garage is the usual starting point. EnSmart’s ELV-W wall pack is IP50, so it stays indoors; the SolarAll-H inverter is IP65 and the ELV-F floor packs IP55. A Powerwall 3 is 1105 × 609 × 193 mm and 130 kg, floor- or wall-mounted, and runs from −20°C to 50°C. Sigenergy’s modules are 767 mm wide and weigh 62 or 78 kg each; a 5 kW controller on two 6.02 kWh modules comes to about 142 kg (our arithmetic on the datasheet weights), and Sigenergy recommends 10–30°C for battery life. EcoFlow fits heating pads to the PowerOcean and offers wall or floor mounting, but publishes no pack weight. Fox ESS’s EP5 is 380 × 625 × 147 mm and about 50.5 kg, and its warranty asks for 300 mm of clearance around the pack, which a crowded garage may not give.
Flats are where siting stops being the first question. In Elmbridge 20.7% of households live in purpose-built flats, and in the two Redhill wards 36.9% do; the freeholder’s consent comes before any brand.
Warranty terms, as each manufacturer publishes them
- EnSmart: the ELV-W datasheet lists a five-year product and ten-year performance warranty, while EnSmart’s other website describes a 10-year warranty. The 15-year figure is a design life, not a warranty, so we put the exact terms in writing with the quote.
- Tesla: ten years, with 80% of capacity retained for UK installations, for a Powerwall bought from Tesla or a Tesla certified installer; registration and an internet connection protect the full term.
- Sigenergy: a 10-year limited product warranty on modules and inverters, with 60% usable energy at ten years or a throughput cap, whichever comes first, and an internet connection required.
- EcoFlow: a published 15 years of daily use until the battery reaches 70% of its original capacity, with registration and correct installation among the conditions.
- Fox ESS: ten years on EP-series batteries to 70% or a throughput limit; the inverter gets ten years only if connected to Fox Cloud within 120 days of installation, otherwise five.
Backup is designed in, never assumed
Ofgem’s 2024/25 figures show about 42.2 supply interruptions per 100 customers and 30.4 minutes lost per customer on South Eastern Power Networks, and about 41.8 and 51.2 on Southern Electric Power Distribution. Those are licence-area averages, not a forecast for your road. None of the five keeps a house running in a cut by default: Tesla needs its Backup Gateway 2, Sigenergy its Energy Gateway, Fox ESS an EPS circuit, and EnSmart’s SolarAll-H UPS function and EcoFlow’s backup output only work on an installation designed and wired for them.
What we can show you
The EnSmart SolarAll cabinets in our job photos are the system we can talk about from the installation side. For the local detail behind the figures above, see battery storage in Guildford, Farnham and Reigate, or our earlier national four-brand comparison. Ask for a Surrey survey, or call 0204 547 1892.
Sources: EnSmart SolarAll-H and ELV datasheets as cited on our EnSmart product page; Tesla Powerwall 3 UK datasheet (2026) and Tesla Powerwall Warranty, European Warranty Region, Rev. 1.16; Sigenergy Battery 6.0/10.0 and Energy Controller (version 20260330) datasheets and Europe warranty (27 May 2025); EcoFlow UK PowerOcean product pages; Fox ESS EP5 datasheet V1.5, H1-G2 datasheet V2.0, UK battery warranty policy V4.5 and inverter warranty policy V2.3; ONS Census 2021, TS044 Accommodation type; PVGIS 5.3, European Commission Joint Research Centre (PVGIS-SARAH3 2005–2023), runs of 15–16 October 2026; UK Power Networks licence boundaries (December 2024); NESO GB DNO licence areas (May 2024); SSEN Distribution, Who we are; Energy Networks Association EREC G98 Issue 2 (10 March 2025); Ofgem, RIIO-2 Electricity Distribution annual report 2024 to 2025, supplementary datafile.