RELATED: What size home battery do I need?
When a battery pays and when it does not
A battery only saves money if you fill it cheaply and use it when power is dear. Two routes do that.
The solar route stores the surplus your panels make at midday. Without a battery that surplus exports to the grid, typically for 10p to 13p a unit on Smart Export Guarantee tariffs. With one, you use it in the evening instead of buying at 26.11p. Roughly double the value from the same sunshine.
The night rate route charges the battery overnight on a smart tariff at around 8p to 10p, with the best EV tariffs closer to 7p. The house then runs through the day on stored power. No panels needed.
If you have neither solar nor a smart tariff, a battery struggles to pay back inside its warranty. Switching to a two rate or EV tariff usually unlocks the numbers, and we will tell you at survey if it does not, rather than sell you a box that does not fit.
Two routes, side by side
Both routes turn a cheap unit into an expensive one avoided. The table shows how the saving builds on a 10kWh system.
| Solar route | Night rate route | |
|---|---|---|
| How the battery fills | Surplus from your panels | Grid at ~8p to 10p overnight |
| What it replaces | Evening import at 26.11p | Daytime import at 26.11p |
| Saving per unit stored | Around 13p to 16p at current export rates | Around 16p to 19p before losses |
| Needs solar panels | Yes | No |
| Typical yearly saving (10kWh) | £200 to £600 on top of solar | £500 to £600 cycled daily |
| Works best for | Homes exporting midday surplus | Homes on a smart or EV tariff |
Most of our customers end up doing both. Solar fills the battery in summer. Night rates fill it in winter.
What about payback?
Payback figures vary a lot online, so we will be straight with you. Current studies put it at around 7 to 12 years for a well matched system on a smart tariff, and longer for a battery on a flat tariff with light use. The honest answer depends on your tariff, your usage and the size fitted.
Two things help the numbers right now. Supply and install home battery projects in England, Scotland and Wales carry 0% VAT until 31 March 2027, including standalone batteries fitted without solar. That covers every install we do. And every battery we fit comes with a 10 year warranty, so a system that pays back in year 8 still has years of saving left inside cover.
We size off your actual consumption, not a guess. That is the difference between a battery that pays and one that sits half empty, and it is how we approach every battery storage installation. Cheaper borrowing is also on the way. The Warm Homes Loan Scheme is expected to cut interest rates on battery and solar loans from late 2026.
