Hardware · Cost note
Fox ESS fitted cost in the UK
Updated
September 2026 illustrations for a Fox hybrid and around 10 kWh often land roughly £4,800 to £7,800 fitted at 0% residential VAT, with board upgrades and scaffolding on top when they apply. Households that want modular capacity, a mainstream hybrid and a price below the Powerwall, with an installer who fits this range every week.
What the illustration includes
Fox ESS hybrids such as the H1 and H3 families are widely fitted in the UK with modular high-voltage batteries. They suit new solar and inverter-replacement retrofits. An older string inverter can stay only if you choose an AC-coupled design instead.
Expect a product warranty in the region of 10 years, and ask which company in the UK handles a cell claim after year six, not just the installer's workmanship year.
A September 2026 figure for Fox ESS
Take a 10.2 kWh pack, cycled about 320 times, at 90% round trip. Charge at 13.0p, and value what comes back at 29.6p. Export given up is priced at 10.0p. About 2469 kWh a year of the charge is treated as spare solar from 4 kWp that might otherwise have been exported. Delivered energy is about 3888 kWh. After charging cost and lost export, the figure saves about £713 a year. Set that against £7,965 fitted, which is a September 2026 illustration at the temporary 0% residential rate, not a quote. That is a simple payback of about 11.2 years on these assumptions. Nudge the night rate up by 4p and see if you still like it.
In most single-phase houses in Britain, 5 kW sits above the 3.68 kW G98 line, so this wants a G99 application before anyone energises it. Export can still be capped. Agree that before the inverter is ordered. The figure uses 10.2 kWh and 4 kWp, which is enough to tell two quotes apart if they assumed something else.
At a steady 600 W evening load, 10.2 kWh lasts about 17.0 hours. A 3 kW kettle only works if the inverter can deliver it. Capacity on the badge does not answer that.
VAT, paperwork, refusal
Where the job is a qualifying install in a home, the 0% rate runs to 31 March 2027 and is due to become 5% after that. This figure prices the work at £7,965 on that basis. It does not apply to a shop, and it does not apply to a battery you buy and fit yourself.
I would not sign off a 10.2 kWh install from a video call. Someone has to open the consumer unit.
Ask the installer for the last Fox ESS they commissioned: postcode area, inverter size, and whether G99 was required. A first-ever install of this range is a risk you can choose not to fund.
Common questions
Is the price on this page a quote?
No. £7,965 is a September 2026 illustration for a 10.2 kWh example at the temporary 0% residential rate. Your survey replaces it.
Will it stay on in a power cut?
Only if a gateway or essential-load board was designed and paid for. A standard grid-tied battery turns off with the grid. On this 10.2 kWh example the inverter is 5 kW, and backup is still a separate line.
What paperwork should I keep?
Keep the MCS certificate where the job is certified, the electrical certificate, the DNO record, the schematic, the warranty registration and a photo of the schedule. For an illustrated £7,965 job, that folder is part of what you bought.
What if the cheap rate is not 7p?
Then the figure changes. This page used 13.0p as a charge rate and 29.6p as the rate avoided. A smaller gap means a worse payback. Read the live tariff.
Sources
Want a price for your house?
The figures above are a rough guide. An installer still needs to see your fuse board, where the battery will go, and whether you want power during a blackout.