If you live in a north London semi, choosing a home battery is mostly a question of which wall. If you live in a flat, it is first a question of whose wall. The split is sharper here than anywhere else we cover: 41.2% of Havering’s 101,277 households live in semis, more than double London’s 18.6%, while in Wembley Park ward 98.2% of households live in purpose-built flats (ONS Census 2021). This guide sets five battery systems against those homes using only the manufacturers’ published figures. For the system we fit ourselves, see EnSmart battery installation in north London.
The roof side of the same question is on solar panels in north London, and the general sizing method is in our battery storage guide. Borough detail sits on our pages for battery storage in Harrow, Enfield and Romford.
The five systems against north London homes
| System | Published build and sizes | Enclosure | In a north London home |
|---|---|---|---|
| EnSmart SolarAll | SolarAll-H hybrid inverter, single-phase 3–6 kW; wall packs of 5.12 or 10.24 kWh; floor packs of 15 or 20 kWh | Inverter IP65; wall packs IP50, indoor only; floor packs IP55 | A Havering semi’s garage or utility room suits the wall pack; an Enfield mid-terrace with no spare room points to the floor packs |
| Tesla Powerwall 3 | One 13.5 kWh unit with a built-in solar inverter, or AC-coupled to an existing one; 130 kg | IP55; IP67 on battery and power electronics | Suits a Romford side wall or garage; a Muswell Hill conversion rarely has a position the leaseholder controls |
| Sigenergy SigenStor | Hybrid controller with 6.02 or 9.04 kWh modules, up to six; 62 or 78 kg a module | IP66 | The stack grows upwards, which can suit a narrow Walthamstow side return if the floor takes the weight |
| EcoFlow PowerOcean | Hybrid inverter with 5 kWh packs, up to 20 kWh on one single-phase inverter | IP65, heating pads | No pack weight or size is published, so the survey has to prove the space in a Barnet garage |
| Fox ESS | H1-G2 hybrid inverter, 3.0–6.0 kW; 5.18 kWh EP5 units, up to four; 10.36 kWh EP11 units | IP65 | An EP5 is 380 x 625 x 147 mm, plus the 300 mm clearance Fox ESS’s warranty asks for |
Semis in Havering, Harrow and Kenton
Harrow’s 89,642 households are 37.1% semi-detached, and in Kenton West ward 64.7% live in semis (Census 2021). A semi there usually offers a side return, a garage or a utility room near the meter, and each of the five systems has a credible position in one of them. The real difference is indoor against outdoor. EnSmart’s wall pack is IP50 and lives indoors, with the IP65 inverter beside it or outside; the other four publish outdoor-rated enclosures, from Tesla’s IP55 to Sigenergy’s IP66. For an unheated Havering garage, EcoFlow builds heating pads into its packs, Fox ESS publishes an EP5-H variant rated down to −25°C, and Tesla gives an operating range of −20°C to 50°C.
Conversions and flats, from Muswell Hill to Wembley Park
Enfield’s 120,923 households are 28.9% terraced and 30.4% in purpose-built flats, and in Muswell Hill ward the largest group, 32.6%, live in part of a converted or shared house. In a conversion or a block, the order is fixed: the building owner’s permission first, which UK Power Networks requires before storage work on a multi-occupied building; then a space you control; only then a brand. Weight decides the wall: 130 kg for a Powerwall, 62 or 78 kg per Sigenergy module, about 50.5 kg for a Fox ESS EP5. In Haringey, the Noel Park, Tower Gardens and Peabody Cottages Article 4 directions withdraw the solar permitted-development right on street elevations; they do not mention batteries, but an indoor or rear-wall position leaves the street front as it is.
Sizing against a north London December
PVGIS gives a 4 kWp south-facing array about 138 kWh in December at Edgware and 143 kWh at Tottenham and Romford, against 474 to 489 kWh in June. On our arithmetic, a midwinter day gives about 4.5 to 4.6 kWh: under one EnSmart, Fox ESS or EcoFlow pack, and about a third of a Powerwall’s 13.5 kWh. So the battery is sized to your evening use, not to winter self-sufficiency, and the smaller steps of the modular brands let you start low and add later. Our borough-by-borough December and June figures set out the seasonal gap in more detail.
Eastern or London Power Networks, and what backup needs
Most north London town centres we cover, from Barnet and Harrow to Enfield and Romford, are in UK Power Networks’ Eastern Power Networks area; Walthamstow’s is in London Power Networks. Equipment up to 16 A per phase (3.68 kW) is notified under G98; above that a G99 application is approved before work starts. Fox ESS lists its 3.7 kW H1-G2 at 3,680 VA for G98 and Sigenergy’s 3.6 kW controller runs at 16.0 A, so the inverter size, not the brand, sets the route.
Ofgem’s 2024/25 figures show about 44.6 supply interruptions per 100 customers for Eastern Power Networks and about 11.2 for London Power Networks. None of the five gives backup by default: Tesla needs a Backup Gateway 2, Sigenergy the Sigen Energy Gateway, Fox ESS covers nominated circuits through EPS, and EcoFlow and EnSmart only when the installation is designed for it.
Warranty terms, and who supplies the unit
In Havering, where 69.5% of households own their home (Census 2021), it is worth knowing what each warranty does when the house is sold, so read the document, not the headline. Tesla gives 10 years, with 80% retained for UK installations, but only for a Powerwall bought from Tesla or a Tesla certified installer; it transfers to a later owner with proof of ownership. Sigenergy gives 10 years to 60% usable energy or a throughput cap, with an internet-connection condition. EcoFlow publishes 15 years to 70% of original capacity. Fox ESS gives 10 years on EP batteries, and its inverter keeps 10 years only if connected to Fox Cloud within 120 days. EnSmart’s product pages publish a 15-year design life, which is not a warranty, so we put the terms for your system in writing.
The battery systems in HCE’s own job photos are EnSmart. For any other brand, ask us and we will confirm in writing how it would be supplied, who installs and commissions it, and what warranty attaches. If a car is part of the plan, DVLA counts 12,097 privately kept plug-in vehicles across Barnet (June 2026), up from 10,089 a year earlier; Sigenergy offers an optional DC charging module with a 3-year warranty, and EnSmart’s SmartBee-M is the charger in our own job photos.
Whether yours is a Havering semi or a flat in a Harrow block, tell us which when you ask for a north London battery survey or call 0204 547 1892.
Sources: ONS Census 2021, TS044 Accommodation type and TS054 Tenure via Nomis (Havering, Harrow, Enfield, London; Kenton West, Muswell Hill and Wembley Park wards); UK Power Networks, Solar and storage: cost, time and what’s involved (read 15 October 2026); UK Power Networks licence boundaries (December 2024) and NESO GB DNO licence areas (May 2024); ENA Engineering Recommendation G98 Issue 2 (10 March 2025); London Borough of Haringey, Article 4 directions; PVGIS 5.3, European Commission Joint Research Centre (PVGIS-SARAH3 2005–2023, 4 kWp, 35°, due south, 14% losses), runs of 15 October 2026; DfT and DVLA, VEH0142, privately kept plug-in vehicles (published 23 September 2026); Ofgem, RIIO-2 Electricity Distribution annual report 2024 to 2025, supplementary datafile (published 15 January 2026); EnSmart and UK-distributor published SolarAll-H, ELV and SmartBee-M documents; 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 datasheets (read 19 October 2026) and Europe warranty (27 May 2025); EcoFlow UK PowerOcean product pages (read 19 October 2026); Fox ESS EP5 datasheet V1.5, H1-G2 datasheet V2.0, UK battery warranty policy V4.5 and inverter warranty policy V2.3.