Fox ESS vs Growatt

Fox ESS and Growatt are the two names most often quoted back to householders when a hybrid inverter and battery quote lands on the kitchen table. Both are Chinese-headquartered manufacturers selling into the UK through installers, both offer hybrid inverters that pair with their own batteries, and both run cloud monitoring. The difference is where each one's weight sits. Fox ESS states that S&P Global Insights data places its UK domestic solar and storage market share at more than 35%, and that SunWiz verified it as the UK's number one brand by volume for both inverters and energy storage systems in Q2 2026¹. Growatt states that it has more than 43 representative offices worldwide and systems installed in more than 180 countries, with more than 1.7 million end users connected to its cloud platform².

For a household, the practical question is not which company is bigger but what each system does to your dependence on the grid and on a supplier. A hybrid inverter plus battery lets a home store its own generation and discharge it in the evening, which cuts the units bought from a supplier. It does not remove the connection: the big six suppliers still held 91.2% of the domestic electricity market in Q1 2025, and Octopus Energy became the biggest domestic electricity supplier in the UK in 2025³. Both brands leave you on the grid, on a supplier's tariff, and on a manufacturer's cloud for monitoring.

Fox ESS vs Growatt at a glance

The two ranges overlap at the hybrid inverter, where a single unit takes DC from the roof, manages a battery and exports or imports through the grid connection. Fox ESS's current single-phase H1 G2 family runs from a 3,000 W rated model to a 6,000 W rated model, with maximum array power of 6,000 Wp on the smaller unit and 12,000 Wp on the larger, and charge and discharge power up to 6 kW⁸. The WL variants add a maximum output apparent power of 3,300 VA at 3,000 W rated and 6,600 VA at 6,000 W rated, with an intermediate WL model listed at 4,048/3,680 VA, and a power factor of 1 adjustable from 0.8 leading to 0.8 lagging⁹.

Growatt's hybrid line spreads wider across phases and formats. The MOD 3000TL3-HU and MOD 6000TL3-HU are three-phase battery-ready hybrids, the SPH 7000TL3-BH is a three-phase hybrid, and the WIT range extends the same approach with a low-voltage battery¹⁰. At the off-grid end sits the SPF 6000ES Plus, a 6 kW off-grid inverter with an 80A AC charge current and generator input, which prioritises PV first, then the battery, and only then the grid or the generator¹³.

Two large makers, two different stories: scale versus UK market leadership

Fox ESS describes itself as a Sino-British partnership, supported by significant international shareholders alongside UK-based stakeholders, operating in more than 90 countries with five R&D centres and more than 5,000 employees¹⁵. Its UK claims are specific and dated: more than 35% UK domestic solar and storage market share on S&P Global Insights data, number one by volume for inverters and ESS in Q2 2026 per SunWiz, second globally for residential energy storage shipments, and first among residential ESS suppliers in InfoLink Consulting's 1H26 global shipment rankings¹. It also states that it is recognised as a BNEF tier 1 energy storage manufacturer¹.

Growatt's published story is one of global spread rather than a single national lead. It describes itself as one of the world's largest manufacturers of PV inverters and energy storage systems, present in the PV market for well over a decade, supplying residential, commercial and industrial installations in dozens of countries¹². Its headline numbers are 43+ representative offices worldwide, 180+ countries with systems installed, and 1.7M+ end users connected to its cloud platform². No UK market share figure is published on the pages reviewed.

The distinction matters to a household because UK market share is a proxy for installer familiarity, spare parts held in the country and the practical speed of a service visit. A brand with a claimed 35% share of the UK domestic sector has a large installed base for an installer to draw on. A brand with 180+ countries of installations has scale, but scale spread across many markets is not the same as depth in one. Both sets of figures are the makers' own statements about third-party rankings, and neither is an independent register a household can inspect directly.

What each company makes: inverters, batteries and the wider ecosystem

Fox ESS develops high-voltage residential battery systems for a range of home energy storage applications, and its guidance describes them as designed to operate with compatible hybrid inverters as part of an integrated residential energy system¹⁴. The EQ battery range carries a 12 year warranty and uses natural convection cooling, while the EP range is IP65 rated and slimline for wall mounting⁵. The company also publishes a modular design approach, describing scalable storage systems where the modular build gives maximum scalability and flexibility in applications¹⁴.

Growatt's ecosystem is broader in format. Alongside the three-phase MOD and SPH hybrids and the WIT low-voltage hybrid, it sells the SPF 6000ES Plus off-grid inverter, which accepts a low-voltage 48 V DC battery class and lists compatible batteries including the AXE 5.0L-C1, ARK 2.5L-A2, HOPE 5.0L-B1 and HOPE 14.3L-A1¹³. It sells pre-built kits, including an SPF 6000 ES Plus with a HOPE battery, an SPF 6000ES Plus with an AXE battery, and an SPF 6000ES Plus with an ALP battery⁶. The AXE range is a low-voltage LiFePO4 battery kit, and the AXE 40H-E1 is a rack format⁷.

The practical difference is voltage class and integration. Fox ESS's residential line is built around high-voltage batteries matched to its own hybrids. Growatt spans high-voltage three-phase hybrids, low-voltage hybrids and a genuine off-grid range with generator input. A household with no grid connection has a Growatt product to look at; Fox ESS's published UK residential range does not include an off-grid inverter.

Market position: Fox ESS's UK and European lead, Growatt's global reach

Fox ESS's market position claims are unusually specific for a manufacturer. Beyond the UK figures, it reports number one market share in Europe's residential energy storage market, a claim it published on 15 September 2026, and it topped global residential ESS shipments in the first half of 2026¹. It also states that Infineon supplies silicon carbide technology to it to enhance the efficiency of residential energy storage systems, a supply relationship announced on 26 August 2026¹.

Growatt's position is stated in cumulative global terms: 43+ representative offices, 180+ countries, 1.7M+ cloud users². It also publishes a UK installation reference, describing a UK residential system where a Growatt SPH 6000 hybrid inverter and a GBLI6532 lithium battery were installed²⁰.

For context on what either brand is displacing, the domestic electricity market remains concentrated. Ofgem's retail market report records that six large companies dominate the domestic market with 91% market share, and that Octopus is now the largest electricity supplier²¹. Independent statistics put the big six's domestic electricity market share at 91.2% in Q1 2025, with Octopus Energy overtaking British Gas to become the biggest domestic electricity supplier in the UK in 2025⁴. EDF Energy is ranked the UK's fifth-largest electricity and gas supplier, and E.ON Next the UK's third largest as of March 2026²².

That concentration is the backdrop to both brands. A home battery does not change who supplies the electricity it buys at night in winter; it changes how much is bought. The independence a Fox ESS or Growatt system delivers is measured in reduced import, not in disconnection.

Monitoring and control: ShinePhone versus Fox's local Modbus control

Growatt's monitoring is a single, well-documented ecosystem. ShinePhone is described by the maker as one app for all Growatt products and as a system monitoring app for users, developed by Growatt itself²⁴. It works with the ShineServer portal over Wi-Fi, and the maker states that the MOD 3000TL3-HU works with the free ShinePhone app and the ShineServer portal, with fault notifications and production history¹⁰. The same pairing appears across the range: the MOD 6000TL3-HU, MIN 5000, SPH 10000TL3, SPH 7000TL3, the WIT hybrids and the SPF 6000ES all list ShinePhone and ShineServer over Wi-Fi¹¹. On the AXE battery, the app and portal show state of charge, charge and discharge power and operating history, with fault notifications⁷.

The accessories extend it. The Shine WiLAN-X2 lets a household monitor production, consumption and battery state remotely in the ShinePhone app and the ShineServer portal, and the Shine GPRS-X is designed to work with Growatt inverters and storage systems that support ShinePhone and ShineServer monitoring²⁶. Growatt confirms compatibility of these accessories before purchase by email, warning that the wrong accessory may not work or may limit system functions¹⁹.

Fox ESS's published position is different in emphasis. Its guidance describes battery systems designed to operate as part of an integrated residential energy system, and the maker's own framing of the installer relationship points to local control and local service rather than a distant platform¹⁴. The company's UK pages present the ecosystem as integrated rather than app-first.

The dependence point is the same for both. Monitoring runs through a manufacturer's cloud, reached over Wi-Fi or GPRS. If the cloud service, the app or the household's broadband fails, the system still runs, but the household's view of it does not.

Where each brand is sold in the UK and what buying means for independence

Neither brand sells direct to householders at a published retail price. Growatt's product pages state that installers and businesses see B2B trade prices after logging in, and that quotes for complete inverter and storage packages come by email¹³. Several Growatt products are listed as available at Growatt.tech, including the SPF 6000ES, the MOD 6000TL3-HU and the MIN 5000¹³. Prices are installer-quoted, and no published retail figure appears on the pages reviewed.

Fox ESS sells through recognised partners, and its warranty terms reflect that route. The Fox ESS battery warranty policy is stated as UK and Ireland only, while the G-Max series warranty applies in all countries where the product is sold through recognised Fox ESS partners²⁷. The company publishes a sales contact at sales@fox-ess.com and gives its address as No. 939, Jinhai 3rd Road, Longwan District, Wenzhou, China¹.

On independence, the picture is mixed for both. A hybrid inverter and battery reduce the units bought from a supplier and shift consumption into self-generated hours. What remains is the grid connection, the supplier and its tariff, the manufacturer's cloud for monitoring, and the installer for anything that fails. Fox ESS has moved into flexibility markets: a January 2026 partnership with Axle Energy is designed to integrate Fox ESS systems into Axle's energy flexibility and market participation ecosystem, enabling customers with Fox ESS battery and solar systems to join one of the UK's leading Virtual Power Plants²⁹. That is a route to earning from a battery, and it is also a further dependence on a third party's platform.

Service, warranty handling and support when something goes wrong

Warranty handling is where the two brands diverge most sharply in the published terms. Fox ESS states that a household's local installer, rather than a distant call centre, typically handles warranty and service issues¹⁵. Its battery warranty policy is explicit about who can claim: the only persons eligible to claim warranty are the installer and Fox ESS authorised personnel²⁷. The G-Max warranty repeats the same condition²⁸. A household therefore cannot pursue a claim directly; the route runs through the installer who fitted the system.

The warranty lengths differ by product. The Fox ESS EQ battery range carries a 12 year warranty, and the EQ/CQ range is listed at 12 years excluding the EQ4800⁵. Growatt's terms are shorter on the off-grid side: the SPF 6000 ES Plus carries a 2 year manufacturer inverter warranty, and the SPF 6000ES Plus with a HOPE battery set repeats the same 2 year inverter term⁶. Growatt's AXE battery is covered by a European service warranty of 5 or 10 years depending on variant, and the SPF 6000 ES Plus with an ALP battery set carries a European service warranty of 10 years⁷. Growatt describes its warranty as a European service warranty across the range².

The practical consequence is that the installer relationship carries more weight than the badge on the box. A brand with a large UK installed base and a stated 35% share gives an installer more reason to hold spares and know the product. A shorter manufacturer warranty on an off-grid inverter is a real cost exposure, and it is stated plainly in the maker's own terms.

Which brand fits which household

The published specifications point to different use cases rather than a ranking. Fox ESS's residential line is built around high-voltage batteries with 12 year warranties, slimline IP65 wall-mounted units and natural convection cooling, matched to single-phase hybrids from 3,000 W to 6,000 W rated⁸. That shape suits a grid-tied home adding storage to an existing or new PV array, where wall space is limited and a long battery warranty is the priority.

Growatt's range covers more ground. A household with no grid connection has the SPF 6000ES Plus, a 6 kW off-grid inverter with generator input, an 80A AC charge current and a low-voltage 48 V battery class, supplied as ready-to-use kits with HOPE, AXE or ALP batteries¹³. A three-phase property has the MOD and SPH hybrids¹⁰. A household wanting a single monitoring app across inverter, battery and accessories has ShinePhone and ShineServer²⁴.

For a household weighing energy independence, the honest summary is that both brands deliver the same category of benefit: self-consumption of generated electricity, some protection from peak import prices, and a battery that can be cycled. Neither removes the grid connection, the supplier, the manufacturer's cloud or the installer. The choice between them turns on voltage class, warranty length, phase, whether an off-grid mode is needed, and which brand the chosen installer actually works with. For the wider picture of how storage fits a home, see adding battery storage to a solar system and hybrid solar inverters.