TL;DR
A home battery in the UK costs £3,000–£9,000 fitted for a sensible 5–10 kWh unit, with premium whole-home kit like Tesla Powerwall 3 pushing towards £13,000–£15,000. Paired with solar, self-consumption jumps from ~45% to ~75% and payback lands around 7–10 years.
LFP has won over NMC for home use. 0% VAT runs on standalone batteries until March 2027. Don’t put it in the loft.
What a home battery actually does
A home battery is a rechargeable box that stores electricity for later. Three jobs, really. It holds surplus solar generated during the day so you use it in the evening, instead of exporting it at 5–15p/kWh and buying it back at 27–30p/kWh. It charges from the grid at off-peak rates overnight. And on the right tariff, it can export at peak rates while you’re still asleep.
That’s the mechanic. The reason it matters: UK homes run most of their load after 5pm, but solar peaks at midday. Without a battery, you throw away the overlap. A typical 4 kWp solar-only system self-consumes around 30–45% of what it makes. Bolt a 5–10 kWh battery on and that number climbs to 70–80%. You’re keeping the cheap electrons instead of selling them at a loss.
Battery inverters are fast. They respond to a load change in milliseconds — so when the kettle goes on, the battery covers it, not the grid. Most owners barely see an import at all between dusk and the small hours. For the ROI detail, the are-solar-panels-worth-it guide runs the full worked numbers.
Battery cost in the UK (2026)
Headline first: expect £3,000–£9,000 fitted for a mid-range 5–10 kWh battery. Premium all-in-one kit like Tesla Powerwall 3 runs closer to £13,000–£15,000 fitted. Prices below include hardware, install labour, 0% VAT and commissioning.
Price per kWh by brand
A useful way to compare is cost per usable kWh installed. Rough 2026 figures:
- GivEnergy All-in-One (13.5 kWh): around £7,500–£9,500 fitted — roughly £600–£700 per kWh. Solid mid-range workhorse, integrated inverter, outdoor-rated.
- Tesla Powerwall 3 (13.5 kWh): around £12,000–£15,000 fitted — roughly £900–£1,100 per kWh. Premium price buys whole-home backup and the Tesla app.
- Fox ESS (e.g. EP5 5.18 kWh modular): around £3,500–£5,500 fitted per module — £700–£850 per kWh. Good value, installer favourite.
- Pylontech (Force-H series, modular): around £650–£800 per kWh. Stackable, cheap per kWh if you’re going larger than 10 kWh.
- Sigenergy SigenStor (modular, 5–30 kWh): around £800–£1,000 per kWh fitted. Newer, very tidy hardware, strong EV integration.
Installation cost ranges
Battery labour sits between £500 and £1,500 depending on scope. A clean retrofit on a garage wall with the consumer unit within 3 metres is the cheap end. Long cable runs, a new sub-board for backup circuits, or a DNO fuse upgrade push you towards the top. Scaffolding isn’t needed for battery-only work — that’s a solar thing.
0% VAT on standalone batteries
Standalone battery installs are zero-rated for VAT until 31 March 2027 under HMRC VAT Notice 708/6. That saves roughly £600–£1,800 on a typical home battery. Every quote we send itemises the VAT line so you’re not guessing. Grants are worth checking too — see the UK solar grants guide for what you actually qualify for.
Sizing your battery
Wrong sizing is the single biggest reason batteries under-deliver. Too small and the surplus you’re trying to capture keeps spilling to the grid. Too big and you’re paying for kWh that never cycle. The sweet spot for most UK homes is 10 kWh.
Battery size vs your solar array
Rule of thumb: battery kWh ≈ your typical evening consumption between 4pm and 10pm. For a 4 kWp solar array on a sunny week, you’ll generate ~20–25 kWh/day, use ~10–12 kWh in daylight, and have 10–15 kWh to store. A 10 kWh battery is the natural match. A 5 kWh battery fills up by 2pm and you’re exporting the rest. A 20 kWh battery won’t fully charge on half the days of the year.
For sizing the solar side to match, see how many solar panels do I need. Array size and battery size want to be specced together.
Battery size vs household consumption
- Small home / low usage (under 2,500 kWh/yr): 5 kWh. Two-bed flat, couple out at work, no EV.
- Medium home (2,500–4,500 kWh/yr): 8–10 kWh. Three-bed semi, two adults, evening-heavy use. The mainstream sweet spot.
- Large home or EV (4,500+ kWh/yr): 10–15 kWh. Four-bed detached, heat pump, EV on overnight charge. Modular stacks like Pylontech, Fox ESS or Sigenergy are a clean way to hit this.
Battery size for time-of-use tariffs
If you’re on Octopus Go (5 hours at 7.5p/kWh), Intelligent Go or Flux, size the battery to fill at off-peak and discharge across the evening peak. Most 5 kW battery inverters can charge fully inside a 5-hour window if the battery is 10–12 kWh. Bigger than that and you don’t fully charge overnight — unless you go to a 6 kW inverter.
LFP vs NMC: why LFP has won in 2026
Short version: every battery we install is LFP (Lithium Iron Phosphate). NMC (Nickel Manganese Cobalt) is older chemistry, still fine in EVs where weight matters, but wrong for a box bolted to your garage wall. Three reasons LFP has won.
Safety. LFP cells are far more resistant to thermal runaway — the chain reaction that can cause a lithium-ion cell to overheat or catch fire. The phosphate chemistry is thermally stable well above 270°C; NMC starts to degrade closer to 200°C. That matters for a battery living inside your home for 15+ years.
Lifespan. Modern LFP cells are rated at 6,000–10,000 cycles at 80% retained capacity. NMC manages about 3,000–4,000. At one full cycle a day, that’s 16+ years vs 10 years in practice.
Depth of discharge. LFP comfortably delivers 90–95% of nameplate capacity every cycle. NMC was typically limited to 80% to preserve cycle life. So a 10 kWh LFP battery gives you roughly 9–9.5 kWh useful; a 10 kWh NMC battery gave you ~8 kWh.
Brands using LFP today: GivEnergy, Tesla Powerwall 3, Fox ESS, Pylontech Force-H, Sigenergy, Growatt, SolaX. NMC has quietly disappeared from UK home batteries. Price has converged too, so there’s no cost case for NMC at home any more. Don’t let anyone quote you NMC in 2026.
AC-coupled vs DC-coupled: which is right for you?
A battery has to talk to the rest of the system somehow. Two ways, and the right one depends on whether you’re retrofitting or starting fresh.
AC-coupled means the battery has its own inverter and plugs in on the household side of your existing solar inverter. Solar DC → solar inverter → AC → battery inverter → battery. Two DC-AC conversions, efficiency around 90% round-trip. Best for retrofits because you don’t touch the working solar kit.
DC-coupled means the battery sits on the DC side, sharing a single hybrid inverter with the panels. One conversion each way, efficiency around 93–95%. Best for new installs. You save ~2–3% round trip and simplify the kit. GivEnergy All-in-One and Tesla Powerwall 3 both support DC-coupling.
The efficiency gap looks small, but across a 15-year life it adds up. That said, don’t bin a working solar inverter to DC-couple a battery — an AC-coupled retrofit is almost always the better call on an existing system. We’ll confirm the right route on survey.
How a battery changes your ROI
Three levers move the money. Self-consumption, cheap-rate charging, and export arbitrage. Most homes will pull two of the three.
Self-consumption uplift
A solar-only 4 kWp system self-consumes around 30–45% of generation. Add a 10 kWh LFP battery and that climbs to 70–80%. Every extra kWh kept in the home is one you don’t buy at 27–30p/kWh import. On a typical system that’s an extra £350–£500 a year saved, before you touch tariffs.
Cheap-rate charging
Time-of-use tariffs are where the real money lands. The leading options on Octopus Energy as of Q1 2026:
- Octopus Go — 7.5p/kWh from 00:30 to 05:30, five hours every night. Ideal for a 10 kWh battery.
- Intelligent Go — 7p/kWh, 23:30 to 05:30, scales the window when you charge an EV. Best for households with an EV.
- Octopus Flux — variable rate, designed around solar and battery owners. Three daily bands: cheap overnight, standard daytime, export- peak from 4pm to 7pm.
- Cosy Octopus — heat pump-friendly tariff with two cheap windows (04:00–07:00 and 13:00–16:00).
Charge at 7–8p, discharge through the evening at avoided import of 27–30p — that’s ~£1.90 a day on a 10 kWh battery cycling fully. Across a year, roughly £600–£700 of pure arbitrage. Ofgem tracks the underlying price cap that these tariffs sit around.
Export arbitrage
On Flux or Agile Outgoing, evening export pays more than standard SEG rates. Charge at 7p off-peak, hold the battery through the day, export at 15p into the 4–7pm peak. It’s a marginal game — maybe £150–£250 a year extra on top of self-consumption — but it’s free money once the system’s there. The full SEG mechanics are in the Smart Export Guarantee guide.
When a battery isn’t worth it
Honest call: a battery doesn’t always pay. If your household uses under 2,000 kWh/yr, if you’re home all day using solar as it generates, or if you’re on a flat standard-variable tariff and never plan to switch, the maths gets thin. For those homes, size the solar properly and skip the battery — or revisit it in two years when a TOU tariff suits you. The solar vs battery-only comparison walks through the edge cases.
Top UK home batteries in 2026
Opinionated tier rundown. Every one below is LFP. Every one is MCS-listed. We install all five.
GivEnergy All-in-One — mid-range workhorse
13.5 kWh in a single outdoor-rated cabinet with the inverter built in. Fit-and-forget, great app, UK-designed firmware. Our most-installed battery in 2025/26 for mainstream 3–4 bed homes. Good if you want a tidy install without the Tesla premium.
Tesla Powerwall 3 — premium whole-home backup
13.5 kWh, 11.5 kW continuous discharge, integrated hybrid inverter, whole-home backup without a separate gateway. The best backup performance on the UK market. Worth it if power cuts matter to you, or if you want the Tesla app ecosystem. Pricey.
Fox ESS — good value
EP5 modules stack from 5.18 kWh up to 31 kWh. Strong installer support, competitive price per kWh, reliable firmware. Best for homes that want modular flexibility without Tesla money. Often the pick when we’re specifying for a large system on a budget.
Pylontech — modular installer favourite
Force-H2 and US5000 series. Rack-mounted, stack up to 25 kWh per stack. Been in the UK market longest, installer base knows them inside out, parts are everywhere. Pair with a Victron, Sunsynk or SolaX hybrid inverter. Best per-kWh price for large systems.
Sigenergy SigenStor — newer, sleek
5 kWh to 30 kWh in a single tower, tidy outdoor IP66 cabinet, built-in EV charger option. Newer to UK but rapidly gaining ground for premium retrofits. Best for homes that want the Tesla-style aesthetic with modular kWh scaling.
Safety, warranty, and installation location
Home batteries are low-risk when installed properly. LFP cells don’t produce dangerous off-gas at normal temperatures, and modern Battery Management Systems cut power instantly on a cell fault. What matters is the install. The UK standards that apply:
- BS 7671 (IET Wiring Regulations, 18th Edition) — the baseline electrical standard every install must meet.
- MCS 017 — the battery installation scheme that certificates a site as professionally fitted. Required for most warranties and for manufacturer support.
- PAS 63100:2024 — the electrical energy storage systems standard from BSI covering siting, protection, and fire safety in dwellings.
- IET Code of Practice on Electrical Energy Storage Systems (2nd edition). Industry best-practice guidance from the IET.
Fire safety matters. Don’t put a battery in the loft where possible. Lofts get hot, access for fire services is poor, and PAS 63100 recommends ground-floor or external installation for new builds and retrofits alike. Garage walls, utility rooms, outbuildings and external weather-rated installs are all fine. If a loft is the only option, we’ll fit a detached fire-rated enclosure and tell you upfront.
Warranties. Every battery we install carries a 10-year manufacturer warranty, with most guaranteeing at least 70% of rated capacity at year 10. Tesla Powerwall 3 is 10 years at 70%. GivEnergy All-in-One is 12 years at 80%. Fox ESS and Pylontech sit at 10 years. Beyond warranty the batteries keep going — LFP cycle life well exceeds warranty terms.
Retrofit vs new install
Two routes in. If you already have solar, you’re retrofitting a battery. If you’re starting fresh, you’re specifying them together. Both work, but the kit and cost shift.
Adding a battery to an existing solar system. AC-coupled is almost always cleanest — the battery gets its own inverter and plugs in on the AC side of your existing solar inverter. Install is 1 day on site, no roof work, no scaffolding. Expect £3,500–£7,500 fitted for a 5–10 kWh retrofit depending on brand and access. If your solar inverter happens to be a hybrid compatible with the battery you want, DC-coupling can work — fewer parts, higher efficiency, but the compatibility list is short. We check on survey.
New solar + battery from day one. Spec the hybrid inverter to match the battery, DC-couple for peak efficiency, commission both at once. One DNO application, one install, one MCS certificate. Usually £1,000–£2,000 cheaper than retrofitting a battery a year later, because you save a second set of paperwork, labour and scaffolding. If you’re still at the “do I get solar?” stage, see solar panel installation for the full install process.
Can’t afford both today? Fit the solar now, make sure the inverter is battery-ready (a hybrid or one with an AC-coupling path), and add the battery later when you’re on a TOU tariff or your bills climb. That’s the most common two-step we see. Use the savings calculator to test both phases.
Frequently asked questions
Can I run my whole house off the battery in a power cut?
Only if the system is wired for it. Off-grid backup (EPS / whole-home backup) needs a dedicated contactor and usually a change at your consumer unit. Tesla Powerwall 3 and GivEnergy All-in-One both support whole-home backup. Most other batteries only run a small essential-circuits sub-board — kettle, fridge, a few lights, Wi-Fi. Flag backup at survey so we spec it correctly — retrofitting it later costs more.
How many cycles does a home battery last?
Modern LFP batteries are warranted for 6,000–10,000 cycles at 80% retained capacity. At one full cycle a day that is 16–27 years of useful life, well past the 10-year manufacturer warranty. Older NMC chemistry managed roughly 3,000–4,000 cycles. This is why we only install LFP.
Do I need a bigger main fuse to add a battery?
Sometimes. UK homes have either an 80A or 100A service head. If you are already close to the limit (induction hob, heat pump, EV charger), adding a 3.68 kW or 5 kW battery discharge can tip you over. We check at survey and, if needed, ask your DNO for a fuse upgrade — free of charge in most regions, roughly 4–8 weeks' wait.
Where's the best place to put a home battery?
Garage, utility room, or outbuilding — cool, dry, and ventilated, easy to reach for servicing. Don't put it in the loft. The IET Code of Practice on Electrical Energy Storage Systems explicitly warns against loft installations because heat builds up and access for fire services is poor. Outdoor wall-mounted units (Tesla Powerwall 3, GivEnergy All-in-One) are rated IP55 or better and suit UK weather.
Can I add a battery to my existing solar system?
Yes. AC-coupled retrofits are the cleanest route — the battery has its own inverter and sits alongside your existing solar inverter, no rewiring of the PV side. Expect £3,500–£7,500 fitted for a 5–10 kWh retrofit. If your existing solar inverter is a hybrid, you can also DC-couple the battery to it — fewer parts, slightly higher efficiency, but the inverter has to be compatible. We'll confirm which route fits your kit on survey.
Do batteries need servicing?
No annual servicing. LFP cells have no moving parts and modern BMS (Battery Management Systems) self-diagnose. Firmware updates roll out over Wi-Fi. The only real check is an eyeball look at the install every few years — clean terminals, no rodent damage, cable glands still sealed. Most owners don't touch theirs between install and inverter swap.
Can I charge the battery from the grid at cheap rates?
Yes — that's where time-of-use tariffs pay off. Octopus Go offers 7.5p/kWh between 00:30 and 05:30. Intelligent Go extends that window when you're also charging an EV. Cosy Octopus and Flux give other cheap windows. The battery charges overnight, discharges through the evening peak at 27–30p/kWh import, and can even export surplus daytime solar at higher Agile Outgoing rates. Arbitrage earns real money on larger batteries.
What happens when the battery degrades?
LFP cells lose capacity slowly. After 10 years a 10 kWh battery typically still holds 8–8.5 kWh usable. Your warranty guarantees 70% capacity at the 10-year mark — claim if it drops below. After warranty, batteries keep working, just with a bit less headroom. Eventually (year 20+) you replace the cells — the inverter and BMS usually outlive them.
Does adding a battery void my solar panel warranty?
Not if we do the work. MCS 017 is the battery installation standard, and our installers are MCS-certified on both PV (MCS 3002) and batteries. Panel and inverter warranties remain intact provided the add-on is carried out to MCS 017, BS 7671 and PAS 63100. DIY battery retrofits can void inverter warranties — don't.
Do I need planning permission for a home battery?
No, for almost every UK home. Battery storage falls under permitted development when installed on a private dwelling. The exceptions are listed buildings and properties in conservation areas with Article 4 directions — check with your local planning authority. The battery itself is smaller than most boilers and sits inside or on an external wall.
