A home solar battery costs roughly £2,800 to £6,500 installed in 2026 for the 5 to 10kWh size most households need, and the full market range runs from under £2,000 to about £10,000. The biggest factor is not the brand but timing: a battery fitted with new panels shares the inverter, the electrician's visit and the paperwork, so it costs less than adding one later. Our 5.8kWh battery adds £2,800 to a solar installation, and a retrofit battery for existing panels starts at £3,995.
- £2,000 to £10,000 market range for home batteries (Which?)
- £400 to £950 typical installed cost per kWh for 5kWh and up
- £3,995 our from price to add a 5 to 10kWh battery to existing panels
- 0% VAT on home batteries until 31 March 2027
- 10 years typical battery warranty, some longer
Solar battery prices in 2026
Battery prices are quoted in very different ways: some without installation, some with, some including VAT from before the zero rate. The fairest comparison is cost per kWh of usable storage, installed. These are published figures from the market and our own prices.
| Battery or package | Capacity | Price | Per kWh | Notes |
|---|---|---|---|---|
| Enphase AC Battery | 1.2kWh | £1,699 | £1,416 | Small modular unit, listed by Which? |
| SolaX battery system | 3.3kWh | from £1,920 | £582 | Listed by Which? |
| Typical 5kWh battery | 5kWh | about £4,600 | £920 | Energy Saving Trust estimate |
| Our battery with new panels | 5.8kWh | £2,800 extra | £483 | 4.4kW package £9,295 vs panels alone £6,495 |
| Our battery retrofit | 5 to 10kWh | from £3,995 | £400 to £799 | Added to existing panels, fully installed |
| Tesla Powerwall | 13.5kWh | £6,200 | £459 | Listed by Which? |
| Any 10kWh battery, installed | 10kWh | £4,000 to £9,500 | £400 to £950 | Range quoted by UK installers |
The pattern is clear: small batteries cost the most per kWh, because the installation, wiring and commissioning cost about the same whatever the size. Past about 5kWh, the extra capacity is comparatively cheap.
What you are paying for
A battery quote bundles several things together. Knowing them helps you compare quotes that look far apart.
- The battery modules. Most home batteries sold now use lithium iron phosphate (LFP) cells, which are more stable than older chemistries. Capacity is what you are mainly buying.
- An inverter. A hybrid inverter runs panels and battery together and is the cheapest route with new solar. For existing panels you either swap to a hybrid inverter or add an AC-coupled battery with its own inverter.
- Electrical work. Isolators, cabling to the consumer unit, a battery meter or CT clamp, and sometimes a consumer unit upgrade if yours is old.
- Grid paperwork. A battery adds to the inverter capacity at your home. If the total goes above 3.68kW on a single-phase supply, the network operator must approve a G99 application before switch-on, which we submit. Under that size it is notified after installation under G98.
- Commissioning and set-up. Programming charge times, linking the app, and registering the system for your MCS certificate so your export tariff carries on.
Fitting with panels or adding later: the difference
| Battery with new panels | Battery added to existing panels | |
|---|---|---|
| Inverter | One hybrid inverter does both jobs | New hybrid inverter, or AC-coupled battery with its own |
| Typical extra cost | From £2,800 for 5.8kWh with us | From £3,995 with us |
| Scaffolding | Already up for the panels | Not needed, battery work is on the ground |
| Install time | Same 1 to 2 days as the panels | Usually a single day |
| Feed-in Tariff risk | Not applicable | Needs care so FiT readings stay valid |
If you already have panels and are weighing it up, see our page on adding a battery to existing solar panels. If you are starting from scratch, the solar and battery packages show the combined prices.
Will a battery pay for itself? A worked example
A battery earns its keep in two ways: storing your own surplus solar, and in winter, charging from cheap off-peak electricity. Here are both, for a 4.4kW system in Birmingham making 4,277 kWh a year.
1. Storing solar you would otherwise export
Without a battery the household uses about 35% of its solar. With a 5.8kWh battery that rises to about 70%, so an extra 35% is used at home instead of exported: 4,277 x 35% = 1,497 kWh.
Each of those units was worth 12p exported and is now worth 26.32p used. The gain is 26.32p - 12p = 14.32p per kWh. So 1,497 x £0.1432 = £214 a year.
2. Charging overnight in winter
From roughly November to March the panels rarely fill the battery. On a time-of-use tariff you can charge it overnight instead. Intelligent Octopus Go, for example, charges 8p per kWh overnight (it needs a compatible electric car). Take 150 days of charging 5kWh at 8p and using it at the 26.32p daytime rate: 150 x 5 x (£0.2632 - £0.08) = £137 a year.
Payback
- Both together: £214 + £137 = £351 a year. On a battery fitted with panels (£2,800), £2,800 / £351 = 8.0 years.
- Same savings on a retrofit at £3,995: £3,995 / £351 = 11.4 years.
- Solar storage only, no overnight charging: £2,800 / £214 = 13.1 years.
Those numbers are honest rather than flattering. A battery on a flat-rate tariff is a slow payback. Paired with a smart tariff it is a reasonable one, and many LFP batteries are designed to keep working well beyond their 10-year warranty.
The one number that decides whether a battery is worth it
It is the gap between your import price and your export price. A battery turns a unit you would have sold into a unit you do not have to buy, so it is worth that gap on every cycle.
- Import at 26.32p, export at 4.1p: gap of 22.2p. A battery is well worth it.
- Import at 26.32p, export at 12p: gap of 14.3p. Worth it with a smart tariff.
- Import at 26.32p, export at 20p: gap of 6.3p. The battery does little on stored solar alone.
So if you have locked in a very high export rate, a battery adds less. If you are on a low one, or a basic SEG tariff, it adds more. Our Smart Export Guarantee guide lists the current rates.
When a battery is not worth the money
- You are home all day and already use most of your solar as it is generated.
- Your system is small (under about 3kW) and rarely has much surplus.
- You are on a high fixed export rate and do not want a time-of-use tariff.
- You would need a battery location that fire guidance rules out, and have no garage, utility room or suitable outside wall.
Where the battery goes
This matters for cost as much as safety. The British Standards guidance PAS 63100:2024 says home batteries should not go in bedrooms, lofts or roof voids, escape routes such as hallways and landings, or cupboards opening off bedrooms, and prefers outdoor locations where practical. In practice that means a garage, a utility room or an outside wall. A long cable run from the consumer unit to a detached garage adds cost, and our surveyor prices this into the fixed quote.
Size and cost go together
Bigger is not always better. A battery that never fills in summer or never empties at night is paying for capacity you do not use. As a starting point, most homes with a 4kW system suit 5 to 6kWh; those with an EV, a heat pump or a larger array suit 10kWh or more. Our guide to what size solar battery you need walks through the sizing, and the best solar batteries in the UK compares brands.
Timing: batteries are zero-rated for VAT until 31 March 2027. At 5% from April 2027, a £3,995 retrofit would cost £199.75 more, and a £2,800 add-on £140 more.
Paying for a battery
Most people pay from savings. The government's Warm Homes Loan Scheme is bringing low and zero interest loans for solar panels and batteries through participating lenders, with the first loans reaching homeowners from autumn 2026, and low-income households may qualify for free installation through their council. Our solar panel grants guide covers who qualifies.
Sources
Battery prices and replacement advice: Which?, solar panel battery storage (May 2026). 5kWh estimate: Energy Saving Trust, battery storage. 10kWh installed ranges: Stratford Energy and Anker SOLIX. VAT: HMRC VAT Notice 708/6. Electricity prices: Ofgem price cap October to December 2026. Tariffs: Intelligent Octopus Go and Outgoing Octopus. Battery location: BSI PAS 63100:2024. Loans: Warm Homes Loan Scheme, gov.uk.
