Places · Street note
Home battery installation in Cardiff
Updated
Cardiff has bay-fronted terraces in Roath and Canton, suburban semis in the north of the city, and apartment stock around the Bay. The terrace and the Bay flat should not be quoted as if they were the same building.
The houses, not the postcode average
Many terraces have a usable rear pitch. Bay-fronted streets can shade the lower roof from a neighbour, so a survey that only uses satellite imagery will be wrong.
Bay flats and managed blocks need the same freeholder test as London, even though the street looks newer and cleaner.
Terraced parking is the usual friction. Bay apartments add concierge and loading rules.
What gets fitted here
A solid Cardiff house job is panels plus 5 to 10 kWh of storage, with the inverter and battery in a garage or a back-of-kitchen cupboard that stays within the manufacturer's temperature range.
South Wales is kinder than Scotland for annual yield, and still not kind in December. Keep a winter tariff in the payback model.
National Grid Electricity Distribution, yield and a 4 kWp example
A 4 kWp array at 980 kWh per installed kilowatt is about 3,920 kWh a year before shade. That is the local ceiling on solar charging, not a promise the battery will cycle fully in January.
In Cardiff, on National Grid Electricity Distribution, 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 10 kWh and 4 kWp, which is enough to tell two quotes apart if they assumed something else.
Take a 10 kWh pack, cycled about 260 times, at 90% round trip. Charge at 11.0p, and value what comes back at 26.0p. Export given up is priced at 4.0p. About 1486 kWh a year of the charge is treated as spare solar from 4 kWp that might otherwise have been exported. Delivered energy is about 2340 kWh. After charging cost and lost export, the figure saves about £438 a year. Set that against £7,018 fitted, which is a September 2026 illustration at the temporary 0% residential rate, not a quote. That is a simple payback of about 16.0 years, which is past a typical 10-year warranty. Nudge the night rate up by 4p and see if you still like it.
What I would not sign in Cardiff
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 £7,018 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 treat backup as included on a 10 kWh quote unless the circuits are listed.
Roath terraces and Bay apartments fail for different reasons: shade and demise.
Common questions
Is the price on this page a quote?
No. £7,018 is a September 2026 illustration for a 10 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 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 £7,018 job, that folder is part of what you bought.
What if the cheap rate is not 7p?
Then the figure changes. This page used 11.0p as a charge rate and 26.0p 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.