The cost depends on whether you are starting from scratch or upgrading an existing battery system.
New battery plus backup — A smaller standard setup with EPS typically starts from around £4,000-£6,000. Premium whole-home systems such as Tesla Powerwall 3 installations sit higher depending on layout, cable routes, and the rest of the electrical setup.
Retrofitting backup to an existing battery — This is often cheaper than a full new installation, but it depends on compatibility and the extra hardware required.
What changes the price: - Battery brand and capacity - Whole-home versus critical-circuit backup - Distance and routing between the battery and distribution gear - Whether consumer unit or electrical upgrade work is required
Current tax position — Domestic battery storage installations currently qualify for 0% VAT until 31 March 2027, which materially improves the numbers.
We provide a tailored quote after survey because backup power projects vary too much to price honestly from a generic package.