Home battery storage in 2026: an honest buyer's guide to costs, savings and choosing the right installer
A home battery stores electricity so you can use it when it is worth more. It fills up from your solar panels or from cheap overnight power, then runs your home in the evening when grid electricity is at its most expensive. Done well, that shaves a real chunk off your bill, gives you power through a cut if you add backup, and puts you in control of when you buy energy. Done badly, you overpay for a system too big to fill each day and the numbers never add up. We are an independent quote and comparison service, not an installer, so we have no reason to sell you the biggest battery. We size to what your home can actually cycle, we tell you honestly when a battery is not worth it, and we match you to vetted, MCS-registered installers so you can compare like for like. This page walks you through everything you need to decide.
The three ways to get a home battery
There is no single "battery installation". There are three routes, and the right one depends on whether you already have solar and what you want the battery to do.
- Solar and battery together. Fitting panels and a battery as one project is the most efficient way to buy. The system is designed as a whole, usually DC-coupled at around 95 to 97 percent efficiency, and you capture daytime sun you would otherwise export cheaply. A full solar-plus-battery system typically runs £10,000 to £16,000. See solar and battery.
- Battery retrofit (adding to existing solar). If you already have panels but export most of your midday surplus for a few pence, a retrofit battery lets you store that power and use it at night instead. It is AC-coupled, around 90 to 92 percent efficient, and cheaper than a full system because there is no roof or new inverter work. See battery retrofit.
- Battery without solar. You do not need solar to benefit. A standalone battery charges overnight on a cheap off-peak tariff and discharges through the expensive evening peak, so you are simply buying electricity at 7p and using it instead of 30p. This works best with an EV, a heat pump or high evening usage. See battery without solar.
How a battery actually saves you money
There are two levers, and most homes pull both. The first is self-consumption: instead of exporting your solar for around 12 to 15p and re-importing in the evening at 24 to 35p, you store it and use your own free power. The second is off-peak arbitrage: on a time-of-use tariff such as Octopus Go or Intelligent Octopus Go you charge the battery at roughly 7p per kWh overnight, then run the house on that stored power through the peak. The best time-of-use spread is around 15 to 17p per kWh saved on every unit you shift. Agile tariffs can drop to 5 to 8p and occasionally go negative, though they are more volatile. If you export, a good tariff pays around 12p flat (Octopus Outgoing) up to roughly 30p at peak on a time-of-use export rate. One honest note: Octopus paused new Flux and Intelligent Flux sign-ups in April 2026, so check what is actually available before banking on a specific tariff. Our savings calculator lets you plug in your own usage and tariff to see the real figure for your home.
2026 cost at a glance, by size
Prices below are typical fully installed UK figures for 2026. Battery-only retrofit sits at the lower end because there is no roof or inverter work. The cost per usable kWh falls as the battery gets bigger, which is why the 10 kWh tier is the most common sweet spot.
| Usable size | Typical installed cost | Cost per usable kWh | Best suited to |
|---|---|---|---|
| 4 kWh | £3,000 to £4,000 | ~£750 to £1,000 | Small homes, low evening use |
| 5 kWh | £3,500 to £5,500 | ~£700 to £1,100 | Under ~2,800 kWh/yr usage |
| 10 kWh | £5,000 to £8,500 | ~£500 to £850 | Typical 3,000 to 4,500 kWh/yr home (most common) |
| 13.5 kWh | £8,000 to £11,500 | ~£590 to £850 | High usage, EV or heat pump, backup |
| 16 kWh | £12,000 to £16,000 | ~£750 to £1,000 | Large high-demand homes |
As a broad rule, budget £500 to £800 per usable kWh installed. Compare by size with our 5 kWh, 10 kWh and 13 kWh guides, or work through the full breakdown on our cost page. For reference, roughly 65 percent of a £5,000 retrofit is hardware, 20 percent labour and 15 percent materials and certification.
Honest payback: what to expect, and what not to
Annual savings depend on size and how hard you cycle the battery. A 5 kWh battery saves roughly £300 to £450 a year, a 10 kWh battery around £550 to £620, and a 13.5 kWh battery around £600 to £750. That is an annual return of roughly 8 to 12 percent. Payback varies a lot by route. Adding a battery to new solar typically pays back in 6 to 10 years; a 10 kWh solar-plus-battery system in 7 to 12 years; a standalone battery with no solar anywhere from 8 to 18 years, though a large battery cycled hard on Octopus Go can get down to 3 to 8 years. We will not pretend a battery pays for itself overnight. If your evening usage is low and you have no EV, we will tell you a smaller battery, or none at all, is the smarter call. That honesty is the whole point of getting an independent quote.
Right-sizing: usable versus nominal, and why bigger is rarely better
The single most common mistake is buying too much battery. A battery only saves money on the energy it actually cycles, so a 13.5 kWh unit that only ever fills to half its capacity is wasted money. First, watch the difference between nominal capacity (the headline number on the box) and usable capacity (what you can actually draw without harming the cells). Always compare on usable kWh. Then match the size to your annual electricity use: under roughly 2,800 kWh a year points to about 5 kWh; a typical 3,000 to 4,500 kWh home lands on around 10 kWh, the value sweet spot; and only high-usage homes with an EV, a heat pump or a need for whole-home backup justify 13.5 kWh or more. If you want cover during a power cut you will also need an EPS or backup gateway, since a standard battery shuts down in an outage for safety. Our backup power and EPS guide explains that setup.
The 0 percent VAT deadline
Right now there is no VAT to pay on domestic battery storage in the UK, including standalone and retrofit batteries with no solar involved. That relief runs until 31 March 2027, after which it reverts to 5 percent. On a £8,000 system the difference is around £400, so if you are already planning to buy, doing it before the deadline genuinely saves money. It is worth knowing this is a real, time-limited saving rather than an installer sales tactic. See our grants and funding page for the full picture on VAT and the schemes worth knowing about.
Brand and warranty security: choose a manufacturer that will still be there
A battery is a 10 to 15 year purchase, so the maker's stability matters as much as the spec. Quality lithium-iron-phosphate (LFP) cells are warranted for roughly 6,000 to 10,000 cycles or 10 to 12 years to around 70 to 80 percent capacity, fading a gentle 1.5 to 3 percent a year. But a warranty is only as good as the company behind it. A clear warning from 2026: GivEnergy Ltd, a major UK residential battery manufacturer, entered administration on 9 April 2026. Existing GivEnergy batteries keep working, but ongoing warranty support, firmware updates and spares are now in serious doubt, and a paid cloud tier was announced. We would not recommend buying a new GivEnergy system today, and we treat it as a cautionary example of why manufacturer stability belongs on your checklist. Well-supported options at the time of writing include Tesla Powerwall 3 (13.5 kWh, around £5,600 supply plus install, with a 10-year unlimited-cycle warranty), Sunsynk in the best-value 10 kWh tier, Fox ESS, and Alpha ESS which is often the cheapest per kWh. Pylontech and Growatt sit in the budget modular space, while Enphase, SolarEdge and Sigenergy sit at the optimised and premium end.
Why comparing independent MCS installers matters
The same battery can vary by thousands of pounds depending on who fits it, and the cheapest quote is not always the best value once you weigh up the workmanship, the warranty terms and the sizing advice. That is why we only match you to independent, vetted, MCS-registered installers. MCS registration is what makes your system eligible for the Smart Export Guarantee and is your assurance the work meets recognised standards. Installation is permitted development with no planning permission needed, but your installer must notify the network operator (a G98 notification for systems up to 3.68 kW per phase, or a G99 application above that). Getting two or three genuine, like-for-like quotes from independent installers is the surest way to a fair price and a properly sized system. Read more in our frequently asked questions, or when you are ready, request your free, no-obligation quotes and we will match you to installers who will size the system to your home, not to their margin.
