Is a home battery worth it in the UK?

The short answer

A home battery is more likely to be worth it when you can charge it cheaply and use that stored electricity instead of buying expensive peak-rate electricity later.

It is less likely to be worth it when the battery is expensive, the difference between peak and off-peak rates is small, or you do not use enough electricity during the times when the battery can help.

The main numbers that matter

• Installed battery cost: the full price you pay, including installation.
• Usable battery capacity: how many kWh the battery can actually deliver.
• Useful peak-period usage: how much expensive electricity the battery can realistically replace each cycle.
• Peak electricity rate: the expensive rate the battery helps you avoid.
• Off-peak electricity rate: the cheaper rate used to charge the battery.
• Battery efficiency: energy is lost when charging and discharging.
• Cycles per year: how often the battery is charged and discharged.

When a battery is more likely to make sense

A battery is usually more attractive when:

• You have a large gap between peak and off-peak rates.
• You use a lot of electricity during expensive periods.
• You can cycle the battery regularly.
• The installed cost is reasonable.
• You plan to stay in the property long enough to benefit.

When a battery may not be worth it

A battery may be harder to justify when:

• Your electricity usage is already low.
• Your tariff has little difference between day and night rates.
• The battery quote is expensive compared with the likely saving.
• You cannot use most of the stored energy.
• The payback period is longer than you are comfortable with.

Simple example

If a battery saves around £600 per year and costs £5,000 installed, the rough payback period is about 8.3 years.

That does not automatically mean it is good or bad. It gives you a starting point for comparing the saving against the cost, warranty period and your own plans.

Best next step

Use the home battery savings calculator to test your own battery size, tariff rates and installed cost.