How much can a home battery save per year in the UK?

A 10kWh home battery on Octopus Go can save approximately £800 per year. A 5kWh battery saves around £400. Savings come from charging at 7p/kWh overnight and avoiding 29p/kWh daytime rates. Actual savings depend on your tariff, battery size, and usage patterns.

How long does a home battery take to pay for itself?

Typically 3-4 years on Octopus Go or Intelligent Octopus Go. After payback, you save £600-800+ per year for the remaining life of the battery. With a 10-15 year lifespan, that's £4,000-8,000+ in net savings.

Do home batteries save money without solar panels?

Yes. A home battery saves money through tariff arbitrage – charging from cheap overnight electricity and discharging during expensive peak hours. No solar panels are needed. You do need a time-of-use tariff with a meaningful off-peak/peak price difference.

How Much Can a Home Battery Save?

The maths

Overnight rate
(Octopus Go)

29p

Daytime rate
(what you'd pay)

22p

Saved per kWh
(every day)

£800+

Typical savings
(10kWh, per year)

Based on Octopus Intelligent Go tariff rates as of January 2026. Actual savings depend on your usage patterns.

Savings by battery size

Battery Size	Daily Savings	Annual Savings	Payback (approx.)
5kWh	~£1.10	~£400	4-5 years
10kWh	~£2.20	~£800	3-4 years
15kWh	~£3.30	~£1,200	3-4 years

These figures assume daily cycling and account for ~90% round-trip efficiency. Your actual savings depend on your usage patterns and tariff rates.

Key point: You don't need solar panels to get these savings. Tariff arbitrage alone – charging when electricity is cheap and using it when it's expensive – pays for the system in 3-4 years.

How the calculation works

Take a 10kWh battery on Octopus Go. The off-peak rate is approximately 7p/kWh, and the peak rate is approximately 29p/kWh. After accounting for ~10% round-trip losses, you get 9kWh of usable energy per cycle.

Daily saving: 9kWh × 22p = £1.98

Annual saving: £1.98 × 365 = £723

In practice, most households see higher savings because daytime rates are often above 29p/kWh and usage patterns mean the battery displaces the most expensive units of electricity first.

Savings by tariff

Tariff	Off-peak rate	Peak rate	Annual saving (10kWh)
Octopus Go	~7.5p	~28p	~£750
Intelligent Octopus Go	~7p	~29p	~£800
Economy 7	~12p	~28p	~£525

What about after payback?

Once your battery has paid for itself – typically in 3-4 years – every year after that is pure savings. With a battery lifespan of 10-15 years, that's potentially 7-12 years of £600-800+ savings. On a 10kWh system, your total net savings over the battery's lifetime could reach £4,000-8,000+.

More savings with solar

If you have solar panels, savings increase further. Instead of exporting surplus solar electricity to the grid at 4-5p/kWh, your battery stores it for evening use – effectively valued at 29p/kWh. A typical 4kWp solar array combined with a 10kWh battery can save £1,000-1,200 per year.

But you don't need solar to start. A battery-only setup delivers strong returns on its own, and you can always add solar later.

Want to see your exact numbers? Use our savings calculator to enter your tariff rates and battery size for a personalised estimate.

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