Places · Case file
AlphaESS for a large detached in Cambridge
Updated
A large house in Cambridge can fit more AlphaESS than the evening will use. Spare wall space in Cambridge is not a reason to buy unused kilowatt-hours.
AlphaESS on a large detached in Cambridge
The hob, the charger and the battery will meet on one single-phase supply. Someone has to say who yields, which is the constraint I would write next to AlphaESS for this large detached.
UK Power Networks covers this Cambridge example. A 4 kWp-class roof at 1000 kWh per kilowatt is about 3,000 kWh a year before shade, and AlphaESS does not change that weather.
Money for AlphaESS for a large detached in Cambridge
Take a 5 kWh pack, cycled about 340 times, at 90% round trip. Charge at 7.0p, and value what comes back at 30.8p. Export given up is priced at 12.0p. There are no panels beside this 5 kWh pack, so every unit charged comes off the grid. Delivered energy is about 1530 kWh. After charging cost and lost export, the figure saves about £352 a year. Set that against £3,869 fitted, which is a September 2026 illustration at the temporary 0% residential rate, not a quote. That is a simple payback of about 11.0 years on these assumptions. Nudge the night rate up by 4p and see if you still like it.
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 £3,869 on that basis. It does not apply to a shop, and it does not apply to a battery you buy and fit yourself.
Connection for AlphaESS for a large detached in Cambridge
In Cambridge, on UK Power Networks, 3.6 kW is in the band where G98 connect-and-notify is often enough. Export can still be capped. Agree that before the inverter is ordered. The figure uses 5 kWh and 0 kWp, which is enough to tell two quotes apart if they assumed something else.
In Cambridge, the weak case for AlphaESS is simple: Whole-home backup briefs and homes with a heat pump, an EV and an electric hob all wanting power at once.
Would I proceed with AlphaESS for a large detached in Cambridge?
I would not sign off a 5 kWh install from a video call. Someone has to open the consumer unit.
I would proceed on AlphaESS for a large detached in Cambridge only after the cupboard, the 3.6 kW connection route and the tariff gap are written down.
Common questions
Is the price on this page a quote?
No. £3,869 is a September 2026 illustration for a 5 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 5 kWh example the inverter is 3.6 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 £3,869 job, that folder is part of what you bought.
What if the cheap rate is not 7p?
Then the figure changes. This page used 7.0p as a charge rate and 30.8p 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.