A home solar battery in the UK costs between £1,500 and £10,000 installed, according to Energy Saving Trust. A 5kWh system costs around £4,600, while a typical home system might be 10 kWh. Therefore, a larger system will sit higher in that range.

The right size depends on how much power you use when the sun is down. The right price depends on whether you fit it with new panels, since the installers are already on site. This guide shows how to size a battery, what drives the cost, and how to check that it earns its place.

What a solar battery does

A battery stores spare solar power for later. Without one, any power your panels make but your home does not use goes to the grid. With one, that power fills the battery first, so you export less.

You then use the stored power in the evening or overnight. That cuts the units you buy from the grid, because you draw on the battery instead. Energy Saving Trust says a battery usually works alongside solar panels, a smart time of use tariff, or both.

Batteries are not perfect. For example, Energy Saving Trust notes that using stored energy is less efficient than using power directly, so you lose some on the way. The system also stops drawing from the battery at a set level, perhaps 20 percent of its capacity, to protect its life.

What a solar battery costs in 2026

Prices vary, so use ranges, not single figures. Energy Saving Trust gives two ranges, both checked in October 2026:

  • Its battery guide says £1,500 to £10,000, with about £4,600 for a 5kWh system.
  • Its solar guide says battery storage tends to cost around £5,000 to £8,000.

The gap between the two is real. It shows how much size and make change the price, because larger batteries cost more. Always get several written quotes. Energy Saving Trust recommends at least three quotes from installers certified with MCS.

Fitting a battery with new panels can cost less. Energy Saving Trust says that installers already on site can connect the panels and battery in the same job. Our guide to how much solar panels cost explains how to read a full quote.

VAT also affects the price. However, the zero rate is temporary. In Great Britain, HMRC’s manual says the temporary zero rate runs from 1 April 2022 to 31 March 2027. A battery installed at the same time as solar panels counts as part of a single zero-rated supply. Since 1 February 2024, batteries added to existing panels and standalone batteries also qualify. In Northern Ireland the zero rate has applied since 1 May 2023. Our post on 0% VAT on solar panels and batteries covers the detail.

How to size a battery

Energy Saving Trust says there is no exact formula. Even so, you can work out a starting point with your own bills.

First, find out how much power you use from sunset to sunrise. Your smart meter or app may show this, although some homes need to ask the supplier. Then compare it with how much spare solar power your panels make on a typical day.

A battery bigger than your spare solar power is wasted money, because it will rarely fill. A battery much smaller than your evening use runs out early, so you still buy a lot from the grid. Aim for a size that fills on most days and empties most evenings.

Here is a simple example. One Energy Saving Trust case study household used about 3,300 kWh in a year, including car charging. That is roughly 9 kWh a day in total. Evening use is only part of that, so a 10 kWh battery would be large for this home. Your own numbers will differ, however, so test them against your meter data.

Our guide to how many solar panels you need helps you match panel size to the battery.

Does the battery pay for itself?

Sometimes. Energy Saving Trust says savings can be significant, but will not always be enough on their own to justify the cost. Home Energy Scotland also says a battery does not always recoup the initial investment.

The result depends on the gap between what you pay for grid power and what you earn for exports. For example, Ofgem’s price cap averages 26.32p per kWh from 1 October 2026, excluding VAT. The Smart Export Guarantee typically pays around 12p, according to Energy Saving Trust. So each unit you store and use later beats exporting it by roughly 14p. Our guide to the Smart Export Guarantee explains export rates.

However, a battery also cuts your export income, because less power leaves your home. Home Energy Scotland says that overall savings usually still exceed export payments alone. A smart time of use tariff can help too. You charge the battery when power is cheap and use it when prices are high.

A battery makes the most sense if you are out in the day, use a lot of power in the evening, or run a heat pump. Energy Saving Trust says a battery saves more when it runs a heat pump than when it only stores solar exports, because heat pumps use power for long periods. For a wider view, see whether solar panels are worth it in your case.

How long a battery lasts

A battery will not last as long as your panels. Energy Saving Trust says a typical battery lasts about 10 to 12 years. Home Energy Scotland says 10 to 15 years. In contrast, Energy Saving Trust expects panels to last 25 years or more. Our post on solar panel lifespan and degradation looks at that side.

So plan for at least one battery replacement over the life of the panels. Ask about the warranty and what it covers, because terms vary by maker.

The inverter matters here, because the battery connects through it. Our guide to solar inverters explains the choices.

Grid rules, diverters and where to start

Your installer should handle any grid paperwork when they add a battery. Our guide to G98 and G99 grid connection explains how the network operator gets involved.

If you only want to use spare solar power for hot water, a solar diverter may suit you if hot water is your main use. A diverter sends spare power to your immersion heater instead of the grid.

To go further, read about choosing a solar installer, then see our hubs on batteries and export, solar panel costs and savings, and how solar panels work.

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Common questions

How much does a solar battery cost in the UK?

Energy Saving Trust says costs run from £1,500 to £10,000, with a 5kWh system around £4,600. Its solar guide gives a typical range of £5,000 to £8,000. Your price depends on size, brand and installation.

What size solar battery do I need?

There is no exact formula. Energy Saving Trust says a typical home system might be 10 kWh and that your installer can advise based on your needs. Start with how much power you use in the evening and overnight.

How long does a solar battery last?

Energy Saving Trust says a typical battery lasts about 10 to 12 years. Home Energy Scotland says 10 to 15 years. Both are shorter than the 25 years or more expected from the panels.

Is VAT charged on solar batteries?

Yes. Installing a battery in a home is zero-rated for VAT until 31 March 2027, in Great Britain and Northern Ireland. Since 1 February 2024 this includes batteries added to existing panels and standalone batteries.

Will a battery pay for itself?

Not always. Energy Saving Trust says savings can be significant but will not always justify the cost on their own. Ask for a written estimate that uses your own usage and your tariff.