Hardware · Cost note
Sigenergy SigenStor fitted cost in the UK
Updated
Fitted stacks are often illustrated from roughly £5,500 for a smaller module count to well over £9,000 once you add modules, a charger option and a harder cable route. EV households that want solar, storage and charging designed together, and homes that may grow from one module to several.
What the illustration includes
SigenStor is a modular stack: battery modules, a hybrid inverter and, on some designs, a DC charger for an EV. It is aimed at homes that want one ecosystem rather than a separate battery brand and a separate charger brand.
Plan on a 10-year conversation and read the retained-capacity clause. Modular systems make it tempting to add capacity later, which is only a benefit if the later module is still sold and compatible.
A September 2026 figure for Sigenergy SigenStor
Take an 8 kWh pack, cycled about 320 times, at 90% round trip. Charge at 9.0p, and value what comes back at 29.6p. Export given up is priced at 10.0p. About 914 kWh a year of the charge is treated as spare solar from 2.5 kWp that might otherwise have been exported. Delivered energy is about 2304 kWh. After charging cost and lost export, the figure saves about £461 a year. Set that against £5,630 fitted, which is a September 2026 illustration at the temporary 0% residential rate, not a quote. That is a simple payback of about 12.2 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 8 kWh and 2.5 kWp, which is enough to tell two quotes apart if they assumed something else.
At a steady 600 W evening load, 8 kWh lasts about 13.3 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 £5,630 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 pay the bulk of £5,630 before the DNO route for a 5 kW inverter is known.
Ask the installer for the last Sigenergy SigenStor 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. £5,630 is a September 2026 illustration for a 8 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 8 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 £5,630 job, that folder is part of what you bought.
What if the cheap rate is not 7p?
Then the figure changes. This page used 9.0p 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.