Is a solar battery worth the extra cost?

A battery can help you use more of your solar electricity at home. Whether it pays for itself depends on the extra cost, how often you use it and the electricity prices you pay.

How much extra would a battery cost?

Ask for two prices: the same solar panel system with a battery and without one. Check whether the battery also needs a different inverter, extra wiring or backup equipment.

The difference between the two complete prices is the extra cost you need to compare with the battery’s savings.

Work out what the stored electricity is worth

Using stored electricity can save you buying electricity from the grid later. But when you store spare solar electricity, you give up the export payment you could have earned by sending it to the grid. Some electricity is also lost in storage.

Ask the installer to allow for both of these when estimating savings. A high export rate can make storing solar electricity less attractive financially.

What about charging overnight?

Some tariffs offer cheaper electricity at certain times. A battery can charge then and supply your home when electricity is more expensive.

Compare the whole tariff, including daytime prices and the standing charge. Check whether you need a particular battery and whether the supplier controls when it charges. Ask for these savings to be shown separately from savings made by your solar panels.

Allow for the battery’s lifespan

Energy Saving Trust describes a typical solar battery lifespan of around 10 to 12 years. A long-term savings estimate should allow for the possibility that it needs replacing before the panels.

Check the warranty length, any limit on how much electricity can pass through the battery, and how much capacity is guaranteed at the end of the warranty.

What VAT applies?

Qualifying batteries supplied and installed in homes can receive 0% VAT under the temporary relief running to 31 March 2027. Buying equipment without installation can be treated differently. Ask the installer to show the VAT on your quote and see our solar and battery VAT guide.

Ask for a clear comparison

• The full fitted price, with the battery cost shown separately.
• The battery capacity you can use and how much power it can supply.
• Estimated yearly savings after storage losses and lost export payments.
• Any overnight charging savings, with the tariff named.
• Warranty, likely replacement costs and aftercare.

Our battery guide explains choosing a size and checking backup power.