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Solar batteries: are they worth it?

What a home battery does, what it costs, how much more of your solar you'll use, VAT and loans, and what to ask.

Checked 9 October 2026 · Sources

Solar inverter, battery inverter and battery storage unit fitted on a utility room wall
Solar and battery kit in a family home: solar inverter, battery inverter and battery · Photo: Michael32710, CC BY-SA 4.0

What a battery does

A home battery stores electricity to use later — spare solar from the day, or cheaper electricity from the grid at off-peak times. It can be fitted with new panels, added to an existing system, or installed on its own.

Costs and size

The Energy Saving Trust (EST) says:

  • a typical home battery might be about 10 kWh
  • prices range from £1,500 to £10,000, and a 5 kWh battery costs about £4,600
  • fitting one at the same time as panels can save money
  • batteries typically last 10–12 years — less than panels

Installed home batteries have qualified for 0% VAT since 1 February 2024, including batteries added to existing solar and standalone batteries. The zero rate runs until 31 March 2027.

How much difference it makes

MCS guidance (MGD 003) shows how a battery raises the share of your solar that you use yourself. For a home using 2,500–2,999 kWh a year with about 3,700 kWh of solar:

  • No battery: 14–23% of the solar used at home
  • About 5 kWh usable: 48–54%
  • About 10 kWh usable: 58–60%

(The range depends on whether someone is home all day, half the day or out all day.)

Storing electricity loses a little energy compared with using it directly, and batteries usually stop discharging at a set level, such as 20%, to protect their life.

Is it worth it?

EST says the savings from a battery "won't always be enough on their own to justify the cost". It may save more if you also have a heat pump, or use a time-of-use tariff to charge cheaply — for example, Octopus's Prime Outgoing export tariff pays more between 4pm and 7pm.

Use our savings estimator with and without a battery to compare.

Paying for it

The government's Warm Homes Loan Scheme treats batteries as a separate measure with a loan cap of £15,000, whether standalone or with solar. You must use an MCS-certified installer and product. See grants and loans.

Before you buy

  • Get at least three quotes from MCS-certified installers.
  • Ask for the battery's usable capacity (not just its nominal size) and its warranty.
  • Ask for the installer's self-use estimate with and without the battery.
  • If you have plug-in solar, note that current rules don't allow its output to be stored in a battery.

Sources

  1. Energy Saving Trust: Battery storage
  2. MCS: MGD 003 Solar PV self-consumption guidance
  3. HMRC VAT Notice 708/6: Energy-saving materials and heating equipment
  4. Octopus Energy: Outgoing Octopus export tariffs
  5. DESNZ: Warm Homes Loan Scheme – scheme rules (Sept 2026)
  6. Citizens Advice: Six things to know before plug-in solar panels hit UK shelves

This guide is general information, not financial or legal advice. Rules and prices change, and some differ between England, Wales, Scotland and Northern Ireland — check the sources for your situation.