A simple guide for UK homes

How Much Could You
Save With a Home
Battery in the UK?

A practical way to estimate annual savings, compare tariffs and work out whether the numbers add up for your home.

Meet DC2AC: modern home battery systems — no solar required. Just smarter control over your energy. Discover more →
Meet DC2AC: modern home battery systems — no solar required. Just smarter control over your energy. Discover more →
Meet DC2AC: modern home battery systems — no solar required. Just smarter control over your energy. Discover more →
Meet DC2AC: modern home battery systems — no solar required. Just smarter control over your energy. Discover more →

A simple guide for UK homes

How Much Could You Save With a Home Battery in the UK?

A practical way to estimate annual savings, compare tariffs and work out whether the numbers add up for your home.

Start with the money question

If you're looking at home batteries, you probably want a straight answer: how much could one take off your electricity bill each year?

The answer depends less on the battery itself than on three things: what you pay for the electricity used to charge it, what that stored electricity allows you to avoid paying later, and how much stored energy your home actually uses.

This is different from choosing a battery size. Our guide, What Size Home Battery Do I Need?, looks at capacity and household needs. Here, we're focusing on pounds, tariffs and simple payback.

Your potential savings depend on your household, electricity use and tariff. Try our Product Guidance to explore a system based on the information you provide.

Where do the savings come from?

A battery doesn't make electricity. It moves electricity from one time to another.

For a grid-charged system, the basic idea is simple: charge the battery when electricity is cheaper, then use that stored energy when grid electricity is more expensive.

Ofgem explains that Economy 7 tariffs use separate peak and off-peak prices. Time-of-use tariffs use the same broad principle, although they may have several price periods and different charging windows.

If your tariff charges the same unit rate all day, there may be little or no bill saving from price shifting alone. A battery may still offer other benefits, but those should be considered separately.

The quick calculation

A useful estimate should separate the value of the electricity delivered by the battery from the cost of the electricity required to charge it.

Illustrative saving per cycle = value of grid electricity avoided − cost of electricity bought to charge the battery.

This matters because batteries are not 100% efficient. If a battery delivers 9 kWh to the home, more than 9 kWh may have been bought from the grid to charge it.

For the examples below, we will assume that the battery delivers 9 kWh to the home during the higher-rate period and that 10 kWh was bought during the cheaper period to provide it. This is an illustration of a 90% round-trip efficiency assumption. Actual usable capacity, reserve settings and efficiency depend on the battery and how it is configured.

These examples are designed to explain the calculation. They are not promises of savings and, unless stated otherwise, the tariff figures are illustrative models rather than live supplier quotes.

Three tariff examples

1. Standard single-rate tariff

For illustration, Ofgem's electricity price-cap unit rate for 1 July to 30 September 2026 is 26.11p/kWh for a typical customer paying by Direct Debit. Actual rates vary by region, tariff and payment method and change over time.

  • Electricity bought to charge: 10 kWh × £0.2611 = £2.61
  • Grid electricity avoided later: 9 kWh × £0.2611 = £2.35
  • Illustrative result: about -£0.26 per cycle

Under this simplified example, charging from the grid and discharging later at the same unit rate does not create a tariff-spread saving. Because some energy is lost in the process, it can actually cost slightly more on energy charges alone.

That does not mean a battery has no value. It means you should not expect grid-charging savings from a price difference that is not there.

For some households, financial savings may not be the only consideration. Energy resilience during a power outage may also form part of the decision. Whether a battery can provide backup power depends on the system and how it is installed and configured, so this should not be assumed from battery storage alone.

2. Economy 7 illustrative model

Now assume an illustrative off-peak rate of 13.5p/kWh and a higher rate of 30p/kWh. These figures are examples only and do not represent a current supplier tariff.

  • Charging cost: 10 kWh × £0.135 = £1.35
  • Value of grid electricity avoided: 9 kWh × £0.30 = £2.70
  • Illustrative saving per cycle: £2.70 − £1.35 = £1.35
  • Theoretical 365-day result: about £493 per year

The £493 figure is a theoretical full-cycle illustration. It assumes the battery is charged at the cheaper rate and the full 9 kWh delivered by the battery replaces electricity that would otherwise have been bought at 30p/kWh every day of the year.

3. Time-of-use illustrative model

A time-of-use tariff can have a wider price gap. Assume, for illustration, a low rate of 8p/kWh and a higher rate of 30p/kWh. Again, these figures are an illustrative model rather than a live supplier tariff.

  • Charging cost: 10 kWh × £0.08 = £0.80
  • Value of grid electricity avoided: 9 kWh × £0.30 = £2.70
  • Illustrative saving per cycle: £2.70 − £0.80 = £1.90
  • Theoretical 365-day result: about £694 per year

Again, £694 is a top-line illustration, not a guaranteed saving. The cheap window must be long enough to charge the battery, and your home must use the stored energy while the higher rate applies.

Why the real figure will often be different

A full-cycle calculation is useful for understanding the economics, but most homes will not repeat exactly the same cycle every day.

  • Some days you may use less electricity during the expensive period than the battery has stored.
  • The battery may not always reach the same state of charge during the cheaper window.
  • Usable capacity can be affected by reserve settings and battery operating limits.
  • Battery and inverter efficiency varies with equipment and operating conditions.
  • Tariff prices and low-rate hours can change.
  • The inverter or battery may limit charging or discharge power.
  • Your standing charge is normally unaffected by battery time-shifting.

Rather than applying a generic 'real-world utilisation' percentage, use your own smart-meter consumption data where available. The key question is how much electricity you are actually likely to shift from cheaper hours into periods when you would otherwise buy at a higher rate.

Turn annual saving into a simple payback estimate

Annual saving tells you what might come off the electricity bill. Simple payback compares that estimate with the total cost of the system, including installation where applicable.

Simple payback period = total cost of the system, including installation where applicable ÷ estimated annual saving

For example, if the hypothetical total cost of the system and installation is £4,000 and the estimated annual saving is £500, the simple payback is eight years.

Simple payback is not a financial-return forecast. It does not, by itself, account for battery degradation, maintenance, finance costs, replacement costs, warranty terms, future tariff changes or the time value of money. If solar generation or export payments are part of the setup, those should be assessed separately.

A sensible comparison is to test more than one scenario. If the purchase only looks attractive when you assume a perfect cycle every day, the estimate may be too optimistic.

What figures should you check?

Before estimating savings, have these details ready:

  • Your current peak and off-peak unit rates
  • The exact hours when the cheaper rate applies
  • How many kWh you normally use during the expensive period
  • The battery's usable capacity, not only its advertised capacity
  • The battery and inverter charging limits
  • The total cost of the system, including installation where applicable
  • Any reserve or backup setting you plan to keep

Your electricity bill and supplier account are the best places to confirm your rates. If you have a smart meter, half-hourly usage data can help show whether you actually use enough electricity during the expensive period to benefit from the stored energy.

A quick reality check before you buy

Ask yourself four questions:

  • Is there a meaningful gap between my cheap and expensive rates?
  • Can the battery charge sufficiently within the cheaper window?
  • Will my home use most of that stored energy during the expensive hours?
  • Does the realistic annual saving make sense against the total cost of the system, including installation where applicable?

If the answer to one of these is no, adjust the estimate before making a decision. A lower saving does not automatically make the system a bad fit, but it should be understood before you buy.

Frequently Asked Questions

Can a home battery save money without solar panels?

Yes, where it can charge from the grid at a cheaper rate and the stored electricity replaces electricity you would otherwise buy at a higher rate. The tariff spread, charging losses and amount of useful energy shifted all affect the result.
Will a bigger battery always save more?

No. Extra capacity only helps financially if you can charge it economically and then use that stored energy when it has value. Capacity that remains unused does not create a saving.
Should I use advertised tariff rates in my estimate?

Use the rates on your own bill or supplier account wherever possible. Tariff prices, hours and eligibility can change, so example rates are best used to understand the calculation rather than predict your own saving.
Does a battery reduce my whole electricity bill?

Not usually. It may reduce some unit-rate costs, but standing charges and electricity bought from the grid when the battery is unavailable or depleted will still appear on the bill.

So, how much could you save each year?

The most useful answer is not one headline number. It is an estimate based on your own tariff, the amount of electricity you can realistically shift and how consistently you can use the battery when grid electricity is more expensive.

Start by calculating the value of the grid electricity the battery could replace. Then subtract the cost of the electricity needed to charge it. Apply that to the amount of energy you realistically expect to shift across the year, and compare the result with the total cost of the system, including installation where applicable.

That gives you a much clearer view of whether the financial case makes sense for your home.

But financial savings are only one consideration when looking at home battery storage. Energy resilience, how you use electricity, future changes to your household and whether solar forms part of your energy setup may also influence the decision. We'll explore these considerations individually in future DC2AC guides.

Your potential savings depend on your household, electricity use and tariff. Try our Product Guidance to explore a system based on the information you provide.

Sources

  • Energy Saving Trust — Battery storage guidance
  • Energy Saving Trust — Low-carbon technology and tariff research
  • Ofgem — Economy 7 consumer guide
  • Ofgem — Energy price cap unit rates and standing charges