What drives the cost of a home battery
Three things mostly determine what you pay:
- Usable capacity (kWh) — the headline figure. More storage costs more, but the price per kWh usually falls as capacity rises.
- Chemistry — modern lithium iron phosphate (LFP) batteries are the standard for home use: safe, long-cycle-life and stable.
- Hybrid vs AC-coupled — a hybrid inverter (battery + solar in one) is efficient and tidy for new installs; AC-coupling adds a battery to an existing solar system without replacing the inverter.
Installation complexity, the inverter, and any switchgear also factor in.
Indicative price bands (2026)
Treat these as indicative UK ranges for a fully installed battery, not a quote:
- ~5 kWh: roughly £3,000–£4,500
- ~10 kWh: roughly £4,500–£7,000
- ~15–20 kWh: roughly £7,000–£11,000
Batteries added at the same time as solar often share installation and inverter costs, reducing the per-kWh price. Standalone retrofit batteries cost a little more per kWh but are still very worthwhile on the right tariff.
Payback with time-of-use tariffs
A battery earns its keep in two ways. First, it stores your surplus daytime solar so you use it in the evening instead of buying from the grid. Second — and increasingly the bigger win — it lets you exploit time-of-use tariffs: charge the battery from the grid at a cheap overnight rate and run your home on it during expensive peak hours.
With a well-matched tariff, a home battery can shift most of your consumption to the cheapest rate, and pairs especially well with a heat pump and an EV. Payback depends on your usage and tariff, but the smarter your tariff, the faster it pays.
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Choosing a manufacturer that will be around
A battery is a 10– to 15-year investment, so the stability of the manufacturer matters as much as the spec. The home battery market has seen consolidation — GivEnergy entered administration in early 2025 — and buyers are rightly cautious about warranties that outlive the company backing them.
We fit established, well-supported systems such as the Sigenergy SigenStor and EcoFlow PowerOcean, chosen for build quality, warranty backing and long-term supply confidence. We are happy to explain the trade-offs so you buy with your eyes open.
Retrofitting a battery to existing solar
If you already have solar panels, you can almost always add a battery later. The usual route is AC-coupling: the battery has its own inverter and simply sits alongside your existing solar setup, so there is no need to replace your current inverter.
We assess your existing system, your consumption pattern and your tariff, then size the battery so it is neither too small to be useful nor too large to ever fill. The goal is the shortest sensible payback, not the biggest box.
Battery Cost by Capacity — and When It Pays
Home battery prices scale with usable capacity, and the right size depends on your daily usage and whether you have solar. Realistic fully-installed 2026 figures:
- 5kWh: ~£3,500–£4,500 — suits a smaller home or a top-up store.
- 10kWh: ~£5,000–£6,500 — the popular family size, covering most of an evening peak.
- 15kWh+: ~£7,500–£10,000 — for high users, heat pumps or EV households.
All attract 0% VAT until 2027, whether fitted with solar or retrofitted on their own — a recent rule change that improves the maths.
A battery pays in two ways: storing your own surplus solar (lifting self-consumption from ~40% to ~80%) and charging from the grid at a cheap off-peak rate to use during the expensive peak. Combined, a 10kWh battery typically saves £500–£700 a year, giving an 8–12 year payback against a 10–15 year warranty on quality units like the Sigenergy and EcoFlow systems we install. The economics are strongest when the battery works alongside solar and a heat pump, so all three share the same cheap and free electricity rather than each paying full peak rate.
Frequently asked questions
As an indicative 2026 figure, a fully installed ~10 kWh battery is roughly £4,500–£7,000, depending on the system, inverter arrangement and installation complexity. Fitting it alongside solar can reduce the cost.
On a time-of-use tariff, usually yes. A battery lets you store cheap or solar-generated electricity and use it at peak times, cutting import costs — especially valuable alongside a heat pump or EV.
Almost always, yes. An AC-coupled battery has its own inverter and works alongside your current solar system without replacing the existing inverter.
It becomes hard to honour — which is why we fit established, well-supported brands such as Sigenergy and EcoFlow, chosen partly for long-term supply and warranty confidence.
It depends on your daily electricity use, your solar generation and your tariff. We size it so it is large enough to be useful but not so large it never fills — targeting the shortest sensible payback.
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