How much does a home battery cost?

Battery sizes

Home batteries are sold by how much energy they store, in kilowatt hours (kWh). Look for the usable capacity, which can be lower than the headline figure.

A good installer sizes the battery from what you use in the evening and overnight, and what your panels make on a typical day. A battery that rarely fills up costs more than it saves, so bigger isn't always better.

Ask every installer for:

• the usable capacity in kWh;
• how fast it can charge and discharge, in kW;
• the warranty, and how much capacity it should keep by the end of it;
• whether it can keep some circuits running in a power cut.

With or without solar

A home battery can't be used with a plug-in solar kit. The government's product rules for plug-in solar don't allow it.

With solar panels

The battery fills up with the solar power you don't use in the day and runs your home in the evening. Fitted at the same time as panels, it can share the inverter, the visit and the paperwork. Added later, it may need its own inverter.

Without solar panels

The battery charges from the grid when electricity is cheaper, usually overnight on a time-of-use tariff, and runs your home when it's dearer. The saving depends on the gap between the two rates.

What changes the price

• Capacity. More kWh costs more.
• The inverter. A hybrid inverter can run panels and a battery together. A battery added to an existing system may need its own.
• Fitting. Where it goes, the cable run to your fuse box and any upgrade the fuse box needs.
• Backup. Keeping circuits running in a power cut needs extra switching gear.
• Warranty. Longer warranties tend to cost more.

Installed batteries in Great Britain are zero-rated for VAT until 31 March 2027, including batteries added to an existing system (HMRC, VAT Notice 708/6).

Sources and dates

We checked every figure on this page on 4 November 2026. If a source changes, we update the page and the date at the top.

1. Solar panel costs, Which?. Page dated 30 October 2026Reports the Energy Saving Trust's estimate that a typical system of about 4.5kWp costs around £7,600 to install, that about 4kWp can make more than 3,000kWh a year, and published battery prices from two large energy suppliers (around £2,500, and from £3,995).
2. VAT Notice 708/6: energy-saving materials and heating equipment, HMRC. Zero rate in Great Britain runs to 31 March 2027
3. Plug-in Solar Device Interim Product Specification v2.0, Department for Energy Security and Net Zero. July 2026

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