Last reviewed: 3 September 2026. Prices are ranges published
by UK installers, not a survey of our own — we say so wherever they appear. Electricity prices use the
Ofgem price cap for 1 October to 31 December 2026.
A home battery does not generate anything. It moves electricity through time — from a
cheap overnight window to an expensive evening, or from a sunny afternoon to the moment you actually
cook dinner. That is why the case for one increasingly has nothing to do with solar panels, and why
the number that decides whether it pays is the gap between your cheapest and dearest unit rate, not
the size of your roof.
What it is, physically
A wall or floor-mounted battery, most often lithium iron phosphate, plus an inverter that converts
between the battery’s DC and your home’s AC, plus a controller that decides when to charge and
discharge. It is wired into your consumer unit by a qualified installer. Unlike a plug-in solar kit,
this is emphatically not a DIY product, it is fixed to your building, and it stays there when you
move.
Two architectures exist and the distinction shows up in every quote you will receive:
- Hybrid — a single inverter handles both solar and battery. Efficient, tidy, and
the obvious choice when panels and battery are installed together. - AC-coupled — the battery has its own inverter and sits alongside whatever else
you have. Slightly less efficient, far easier to retrofit, and the only sensible route if you have
no solar or already have an inverter you are not replacing.
You do not need solar panels
This is the most useful thing on the page. On a time-of-use tariff with a cheap overnight window,
you can charge the battery at the low rate and run the house from it through the evening peak, with no
generation involved at all. The saving per cycle is simply the price difference multiplied by the
usable capacity, minus round-trip losses of roughly a tenth.
Since February 2024 a standalone battery, installed without panels, also qualifies for the zero
rate of VAT on energy-saving materials — a relief that runs to 31 March 2027. See
a home battery without solar panels and
charging on a cheap night tariff.
The arithmetic, honestly
Take usable capacity in kWh × the price spread in £/kWh × cycles per year × round-trip efficiency.
A 10 kWh battery cycled once a day on a 20p spread returns roughly 10 × 0.20 × 350 × 0.9 ≈ £630 a
year. Halve the spread and you halve the return. Fail to cycle it fully — because your evening
consumption is 5 kWh, not 10 — and you halve it again while having paid for capacity you never
use.
| Variable | Effect | Under your control? |
|---|---|---|
| Price spread between cheap and peak rates | Directly proportional | Yes — it is a tariff choice |
| Cycles actually completed per year | Directly proportional | Partly — depends on sizing and habits |
| Usable (not nominal) capacity | Directly proportional | At purchase |
| Round-trip efficiency | Roughly 5–12% off the top | Marginally, by product choice |
| Installed cost | Sets the payback period | Yes — by getting three quotes |
| Panel output, if you have solar | Adds cycles in summer, few in winter | — |
Under the price cap for 1 October to 31 December 2026 a flat direct-debit rate is 26.32p per kWh.
A flat tariff offers no spread at all, which is why a battery on a capped standard tariff is close to
pointless without solar: there is nothing to arbitrage. Moving to a time-of-use tariff is therefore
part of the purchase, not an afterthought.
What it costs
UK installers in 2026 publish installed prices broadly in these ranges — with 0% VAT applied, and
before the regional loading that London and the South East typically attract. These are ranges the
trade publishes; we have not carried out our own survey and will label one clearly when we do.
| Usable capacity | Typical installed range | Roughly per kWh |
|---|---|---|
| About 5 kWh | £2,500 – £4,500 | £500 – £900 |
| About 10 kWh | £4,000 – £7,500 | £400 – £700 |
| 13–15 kWh premium systems | Substantially higher; some flagship products exceed £8,500 | — |
What moves a quote inside that range is rarely the cells. It is whether a hybrid or AC-coupled
inverter is needed, the cable run from the battery to the consumer unit, whether anything on the way
needs upgrading, scaffolding or access difficulty, and the installer’s own overhead.
Home battery cost in the UK takes a quote apart line by line so you can
compare two of them meaningfully. We do not sell leads and we do not take a commission on any
installation — see how we make money.
Sizing: the expensive mistake
Oversizing is the most common and costliest error, because capacity you never cycle earns nothing
and still ages. Start from your own half-hourly consumption — your supplier can give you the data from
your smart meter free — and specifically from how much you use between the end of the cheap window and
bedtime. That number, not your roof area or your ambitions, is the size of battery you need.
What size do I need and the
sizing calculator work through it.
The technical choices that actually matter
- Usable versus nominal capacity. A “10 kWh” battery may allow you 9 kWh, or
less. Compare usable figures or you are comparing nothing. - Warranty throughput. Many warranties cap total energy through the battery in
MWh as well as setting a period in years. Daily cycling can reach the throughput cap long before
the tenth anniversary. See how to read a battery
warranty. - Chemistry. LFP dominates the domestic market for reasons of safety and cycle
life: LFP versus NMC. - Siting. Garage, utility room, loft or external wall — with implications for
temperature, building regulations and your insurer:
where a battery can be installed. - Lifespan. Measured in cycles and temperature, not years:
how long a home battery lasts.
Two dates you should know about
31 March 2027 — the zero rate of VAT on installed home battery storage is due to
end, with a return to the reduced 5% rate rather than to 20%. On a £5,000 system that is a few hundred
pounds, which is a real consideration and not a reason to panic-buy. See
the VAT deadline.
9 April 2026 — GivEnergy Ltd, one of the best-known British domestic battery
brands, entered administration and ceased trading, and hardware warranties stopped being honoured by
the company. The installed batteries continue to work, but the episode is the clearest possible
demonstration that a manufacturer’s warranty is only as durable as the manufacturer. See
battery warranties and
what GivEnergy owners should do.
Batteries and plug-in solar
You cannot combine them in one device. A compliant plug-in solar kit is specifically not allowed to
import electricity from your home in order to store it, so the “balcony power station with battery”
products sold in the EU are not compliant on the British plug-in route. A separately installed home
battery and a plug-in kit can coexist in the same house; they simply are not one product. See
can I add a battery to plug-in solar?
Frequently asked questions
Will a battery keep my lights on in a power cut?
Only if it was specified with backup functionality and the appropriate switching, which is an extra
cost and is not standard. Ask explicitly; do not assume.
Is a battery worth it without solar?
It can be, on a tariff with a wide day–night spread and with evening consumption large enough to
cycle it. On a flat capped tariff, no.
Does a battery pay for itself?
Sometimes, over most of its warranted life, if it is correctly sized and cycled daily on a good
spread. Anyone promising a short payback is assuming a spread and a cycle count you should check.
Can I add a battery to existing solar panels?
Yes — that is what AC coupling is for. It is the most common retrofit in Britain.
Does a battery affect my house insurance?
Tell your insurer. Most treat a professionally installed system as a normal fixture, but a
non-disclosure is a poor position to be in after a claim.
Sources.
Ofgem, price cap unit rates and standing charges ·
HMRC, VAT on energy-saving materials (Notice 708/6) ·
MCS.
Installed price ranges are drawn from published UK installer guidance in 2026 and are labelled as
such. Editorial methodology ·
how we make money.