Last reviewed: 5 September 2026. Installed price ranges on this page
are ranges published by UK installers, not a price survey of our own. Electricity figures use the Ofgem
price cap for 1 October to 31 December 2026. Time-of-use tariff rates change frequently — check the
current rates yourself before committing to anything on this page.
Yes, you can install a home battery with no solar panels at all, and for a growing number of British
households it is the better of the two purchases. The battery does not need sunshine to make money. It
needs a price difference between two times of day, and it charges from the grid at the cheap time and
discharges into your house at the expensive one.
This is not a workaround or a loophole. It is straightforward arbitrage, it is what a battery does
best, and since 1 February 2024 the tax system has treated a standalone battery exactly the same as one
fitted alongside panels.
The idea in one paragraph
Under a flat direct-debit tariff at the price cap you pay 26.32p per kWh whenever you use it. Under
a time-of-use tariff you pay much less at night and more during the evening peak. A battery large
enough to carry your house through the peak lets you buy every unit at the night rate. Your annual
saving is your daily discharge multiplied by the gap between the two rates, multiplied by the number of
days you actually manage it, adjusted for round-trip losses.
The arithmetic, at three spreads
The table below assumes 10 kWh of usable capacity, 350 full cycles a year and 90% round-trip
efficiency. Formula: usable capacity × spread × cycles × efficiency.
| Spread | Annual saving | At £4,000 installed | At £5,500 | At £7,500 |
|---|---|---|---|---|
| 10p per kWh | £315 | 12.7 years | 17.5 years | 23.8 years |
| 15p per kWh | £473 | 8.5 years | 11.6 years | 15.9 years |
| 20p per kWh | £630 | 6.3 years | 8.7 years | 11.9 years |
| 25p per kWh | £788 | 5.1 years | 7.0 years | 9.5 years |
Set that against a warranty that typically runs ten years and frequently carries a total-throughput
cap in MWh that daily cycling will reach. Anything in the bottom-right corner is a system that will not
pay for itself inside the period anybody has promised to stand behind it.
Note what is not in that table: sunshine, roof orientation, shading, seasonality. A
standalone battery performs identically in January and July, which is a genuine and underrated
advantage over solar in this country. Its output does not collapse for four months of the year.
Where the spread comes from — and the honest risk
Time-of-use tariffs in Britain currently offer overnight rates well below the capped daytime rate,
with the widest spreads on tariffs designed for EV owners and battery owners. That is where the numbers
above come from, and it is also where the risk sits.
[VERIFICAR: we have deliberately not quoted specific supplier tariff rates. They
change frequently, they vary by region and meter type, and a rate printed here would be wrong within
weeks. Check the current off-peak and peak rates on the specific tariff you would move to, put those
two numbers into the formula above, and use the result rather than ours.]
The uncomfortable part is that your entire business case depends on a commercial product that your
supplier can withdraw or reprice, on a battery you cannot un-buy. Nobody selling batteries says this
plainly. Three defences:
- Model the flat-rate case. If the spread collapsed to zero tomorrow, what would
the battery be worth to you? Standing charges and peak-avoidance aside, close to nothing. Decide
whether you can live with that outcome before you spend. - Check the tariff’s eligibility conditions — some require a smart meter capable
of half-hourly settlement, some require specific hardware, some have exit fees. - Do not size for the best imaginable tariff. Size for your actual evening
consumption, which is the subject of what size home
battery do I need.
VAT: standalone is zero-rated, and has been since February 2024
This is the point most often got wrong. Before February 2024, the energy-saving materials relief
only reached a battery installed alongside solar panels; a retrofit standalone battery attracted the
standard rate. That changed on 1 February 2024, when standalone batteries were brought
inside the relief.
So supply and installation of a battery in residential accommodation is currently
zero-rated whether or not you have panels, and that runs to 31 March 2027. From 1
April 2027 it is legislated to revert to the reduced 5% rate — not 20%. On a £5,500
job that is about £275, not £1,100. If a salesperson uses a 20% cliff edge to hurry you, they are
either misinformed or hoping you are. The full picture is in buying a battery after the VAT change and VAT on home batteries explained.
The error in the other direction matters too: buying a battery as goods and installing it yourself
is not zero-rated. HMRC’s guidance is explicit that supplying energy-saving materials
without installing them is standard-rated. The relief is for supply-and-install.
What a battery without solar does and does not do
| Standalone home battery | 800 W plug-in solar kit | |
|---|---|---|
| Typical cost | £2,500 – £7,500 installed | £300 – £1,000, self-installed |
| Where the saving comes from | Buying units cheap and using them expensive | Not buying units at all |
| Depends on the weather | No | Heavily |
| Depends on your tariff | Entirely | Only through the unit rate |
| Depends on you being home in the day | No — it prefers you home in the evening | Yes, and this decides everything |
| Installation | Qualified installer; G98 or G99 application; building regs notification | Plug it in; G98 within 28 days |
| Portable if you move | No, realistically | Yes |
| VAT | 0% to 31 March 2027, then 5% | Standard rate — it is goods, not an installation |
| Reduces your carbon footprint | Indirectly, by shifting demand to lower-carbon hours | Directly, by generating |
They are not competing purchases so much as answers to different household situations. An empty
weekday house with a wide-spread tariff wants the battery. An occupied house on a flat tariff with a
sunny south wall wants the panels. A household that is out all day and on a flat tariff should fix the
tariff first, before buying anything.
The things that make a standalone install more expensive than you expect
- Consumer unit work. An older board may not take the new circuit safely. Four
hundred to a thousand pounds, and frequently discovered on the day. - Cable run and siting. A garage adjacent to the board is cheap; a loft at the far
end of the house is not. Where a battery may legally and safely go is its own question. - The DNO application. Storage is not a plug-in device — this is a G98 or G99
application depending on rating, handled by the installer, and it can come back with conditions. - Backup during a power cut. Not included as standard. It needs additional
switching, and it must be asked for and priced separately. Many buyers assume they are getting it and
are not. - Continuous power rating. A 10 kWh battery that can only deliver 3 kW will not
carry an oven, a kettle and a tumble dryer at once; you import the difference at peak rate, which
quietly erodes the saving in the table above.
The full anatomy of a quote is in what a home battery costs in the
UK.
Before you buy: the twenty-minute test
- Ask your supplier for your half-hourly consumption data. It is free and it is yours.
- Add up what you use between 4pm and 10pm on a typical weekday. That is the discharge the battery
has to cover — and it is usually smaller than people guess. - Find the off-peak and peak rates on the tariff you would actually move to, and subtract.
- Run the formula: usable kWh × spread × 350 × 0.9.
- Divide the quoted price by that. If the answer is longer than the warranty, walk away or buy
smaller.
Frequently asked questions
Will a battery charge from my plug-in solar kit?
Only incidentally, by absorbing surplus that would otherwise be exported. A plug-in kit cannot
contain a battery — SI 2026/848 excludes devices designed to import electricity to store it. See can I add a battery to plug-in solar.
What if the manufacturer goes out of business?
It happens — GivEnergy Ltd entered administration in April 2026. The batteries kept working; the
warranties did not. See what to do if your
battery brand goes bust and pay by credit card where you can.
Sources.
HMRC, VAT Notice 708/6, energy-saving materials ·
Ofgem, price cap unit rates and standing charges ·
SI
2026/848.
Installed price ranges are published UK installer guidance, labelled as such; payback figures are our
own arithmetic from the stated assumptions. This is general information, not financial advice — see
editorial methodology.