FOX
ESS
Proven reliability. Smart battery storage designed for UK homes. Start saving from day one with a system built to last decades.
Fox ESS System Specifications
| Battery module capacity | 2.88kWh — stackable to 20kWh+ |
| Chemistry | LiFePO₄ (lithium iron phosphate) |
| Hybrid inverter range | 3.0kW – 8.3kW single-phase |
| Round-trip efficiency | ≥ 95% |
| Warranty | 10-year product / extendable to 30-year system cover |
| App & smart control | Fox ESS Cloud — time-of-use, EV & tariff optimisation |
| VAT | 0% on residential battery storage until 31 March 2027 |
Fox ESS Price in the UK (Installed)
Fox ESS is one of the best-value battery brands in the UK, starting from £4,195 fully installed for an entry-level Essential system. Larger multi-module configurations retrofit easily to existing solar and remain competitive against premium brands.
| Configuration | Usable capacity | Typical Installed Price |
|---|---|---|
| Essential (single module + hybrid inverter) | ~5.8kWh |
£4,195
|
| Popular (2 modules) | ~8.6kWh | From £5,295 |
| Family (3 modules) | ~11.5kWh | From £6,195 |
| Large (EP11 / 3× ECS4300) | ~15 kWh | £6,000 – £7,500 |
| Whole-home (EP11 / 4–5× ECS4300) | ~20 kWh | £7,500 – £9,000 |
Prices include hardware, installation, commissioning and 0% VAT on domestic battery storage until 31 March 2027. Final price depends on cable runs (loft vs garage), DNO fees, single vs three-phase and whether PV is fitted at the same time.
About Fox ESS
Fox ESS is a Sino-British battery and inverter manufacturer founded in 2019, headquartered in China with a dedicated Fox ESS UK operation. By 2026 the brand is active in more than 70 countries and was ranked No.1 in Europe and the UK for residential energy storage shipments in H1 2025 by S&P Global, and No.1 globally in residential storage shipments going into SNEC 2026. Fox ESS reports a 30–40% share of the UK residential storage market, distributed through Segen, Midsummer and a wide MCS installer network.
Fox ESS Product Range
The 2026 UK line-up spans stackable high-voltage batteries (EP5/EP11, EP6/EP12), modular ECS batteries (ECS2900, ECS4300), all-in-one AIO hybrids and separate H1/H3 hybrid inverters. Every domestic option uses LFP chemistry with a 10-year warranty and 6,000-cycle rating at 80% DoD.
| Series | Format | Capacity | Typical use |
|---|---|---|---|
| EP5 / EP11 | Floor-standing HV stack | 5.2 – 26 kWh | Most Manchester domestic installs |
| EP6 / EP12 (2026) | HV stack, 6,000 cycles | 5.76 / 11.52 kWh usable per stack | Latest EP generation |
| ECS2900 | Modular HV stack | 2.9 kWh × 1–5, up to 43.5 kWh across 3 stacks | Flexible stepped sizing |
| ECS4300 | Higher-density module | 4.3 kWh × 1–6 (up to ~26 kWh) | Larger 4-bed / EV homes |
| AIO H1 | Single-phase all-in-one | ~10 kWh integrated, 3.7 / 5 / 6 kW output | Clean new-build solar installs |
| AIO H3 / H3 Pro | Three-phase all-in-one | ~10–15 kWh, 8–12 kW output | Large homes / small commercial |
| H1 / H3 hybrid inverters | Separate hybrid | 3.7 – 12 kW AC output | Pair with EP or ECS stacks |
| EQ series | Cabinet / rack | 5–10 kWh modules, up to ~50 kWh+ | Commercial & plant rooms |
LFP Chemistry & Safety
Every Fox ESS residential battery uses LFP (lithium iron phosphate) cells. LFP is significantly more resistant to thermal runaway than NMC/NCA chemistries, which lowers fire risk and makes the batteries suitable for loft, garage and utility-room installs when fitted to MCS and manufacturer guidance.
- 6,000 cycles at 80% DoD — 16+ years at one cycle per day.
- 10-year product warranty tied to cycle and energy throughput.
- IP65-class enclosures with integrated battery management system (BMS).
- Cobalt-free chemistry for improved sustainability and ethical sourcing.
AC vs DC Coupling — Retrofit or New Solar
Fox ESS supports both DC-coupled (hybrid inverter) and AC-coupled configurations. Choice usually depends on whether you're adding storage to an existing PV system or installing solar and battery together.
DC-coupled (H1 / H3 hybrid or AIO)
Best for new solar installs. Fewer AC/DC conversions, higher end-to-end efficiency, cleaner wiring and finer control of PV-to-battery charging.
AC-coupled retrofit
Best for existing solar. Keep your current inverter and add a Fox AC-coupled battery pack — ideal where the existing PV inverter is newer or still under warranty.
Fox ESS Cloud App & Monitoring
The Fox ESS Cloud smartphone app provides real-time monitoring of PV generation, battery state of charge, grid import/export and household load, with daily, monthly and yearly graphs. Installers can set time-of-use charge/discharge windows remotely, making the platform compatible with Octopus Go, Intelligent and Agile tariffs to store cheap off-peak grid electricity for use in the peak evening period.
Fox ESS vs GivEnergy, Tesla Powerwall 3 & Sigenergy
| Brand | Strengths | Trade-offs |
|---|---|---|
| Fox ESS | Lowest £/kWh in this group, 6,000 cycles, 10-year warranty, modular EP/ECS sizing. | Tariff software less advanced than GivEnergy. |
| GivEnergy | Strong UK support, best Octopus Agile/Go integration. | £200–£400 more per comparable capacity; 3,000–4,000 cycles vs 6,000. |
| Tesla Powerwall 3 | 13.5 kWh with built-in solar inverter, seamless whole-home backup. | Higher cost per kWh, fixed capacity, tied to Tesla ecosystem. |
| Sigenergy SigenStor | Highly modular in 5 kWh steps, premium smart backup features. | Higher price point than Fox ESS for equivalent capacity. |
Who Fox ESS Suits Best
- 3–4 bedroom Manchester homes with 3–6 kWp solar and 10–20 kWh daily usage, wanting ~10 kWh of storage to cover evenings and mornings.
- EV drivers on Octopus Go / Intelligent who want to store cheap off-peak electricity, typically with 15–20 kWh stacks.
- Cost-conscious buyers who want LFP safety, a 10-year warranty and 6,000 cycles at a lower price than Tesla or Sigenergy.
- Existing solar owners looking to retrofit storage via AC-coupling or a Fox H1/H3 hybrid inverter swap.
Manchester Installation Considerations
Location & mounting
Garage or utility room preferred for EP/ECS stacks — cooler ambient, easier access. Loft installs are permitted but need ventilation and correctly sized joists. Floor-standing stacks need a level base with rear and side clearance for maintenance.
MCS & DNO G98/G99
All installs are MCS-certified. Typical H1 sizes (3.7–6 kW) are notified to Electricity North West under G98; H3 or exports over 3.68 kW/phase require a G99 application and approval before commissioning.
Tariff setup
Manchester homes on Octopus Go, Intelligent or Agile can configure charge windows in the Fox ESS Cloud app to store cheap night-time grid electricity and discharge across the 16:00–19:00 peak.
Noise & aesthetics
Fox systems run quietly but installers avoid bedrooms for larger stacks. AIO H1/H3 all-in-ones give a neater single-box look for visible utility rooms.
Fox ESS FAQs
How much does a Fox ESS battery cost installed in the UK?
In 2026 typical installed prices in Manchester are around £3,500–£4,500 for a 5kWh class system, £4,800–£6,000 for a 10kWh stack, £6,000–£7,500 for 15kWh and £7,500–£9,000 for a 20kWh system. Greentech Renewables' Essential package starts from £4,195 fully installed, MCS certified with 0% VAT.
How long will a Fox ESS battery last?
Fox ESS uses LFP (lithium iron phosphate) cells rated for 6,000 cycles at 80% depth of discharge. With a 10-year product warranty and typical daily cycling, most Manchester households can expect 12–15+ years of useful life.
Is Fox ESS safe to install in a loft or garage?
Yes. LFP chemistry is highly thermally stable and Fox enclosures are typically IP65-rated. Garages and utility rooms are preferred for cooler operating temperatures, but loft installs are permitted when ventilation, weight loading and MCS guidelines are respected.
Can I add a Fox ESS battery to my existing solar system?
Yes. Fox ESS supports both AC-coupled retrofit (keeping your existing string inverter) and DC-coupled retrofit by swapping to a Fox H1 or H3 hybrid inverter alongside an EP or ECS battery stack.
What size Fox ESS battery do I need for a 3–4 bed Manchester home?
Most 3–4 bed homes with 3–6kWp of solar and 10–20kWh daily use benefit from 8–12kWh of usable storage. A 10.4kWh EP or 3-module ECS4300 stack is the most common Manchester recommendation.
Will a Fox ESS system work during a power cut?
Fox H1, H3 and AIO hybrids support backup circuits when installed with appropriate changeover switchgear. Whole-home backup depends on load size and is designed on a per-property basis at survey.
How does Fox ESS compare to GivEnergy?
Fox ESS is typically £200–£400 cheaper per comparable capacity and rated to 6,000 cycles versus GivEnergy's 3,000–4,000. GivEnergy offers stronger UK-based support and more advanced Octopus Agile/Go tariff integration.
Is Fox ESS a reputable brand?
Yes. Fox ESS was ranked No.1 in Europe and the UK for residential energy storage shipments in H1 2025 by S&P Global, and is active in 70+ countries with a 30–40% share of UK residential storage.
How long is the Fox ESS warranty?
Fox ESS batteries carry a 10-year product warranty as standard, tied to a 6,000-cycle energy throughput limit. Total system cover is extendable to 30 years when installed by an approved Fox ESS installer such as Greentech Renewables.
Is Greentech Renewables a Fox ESS approved installer?
Yes. Greentech Renewables is an approved Fox ESS installer covering Greater Manchester and the North West, fitting Fox ESS hybrid inverters and battery modules alongside MCS-certified solar systems.
Ready for a Fox ESS quote?
Approved Fox ESS installer covering Greater Manchester and the North West.
