Guide: battery savings
How much can a home battery actually save?
There is no useful single UK average. A battery saves money only when it moves electricity from a cheaper source or hour into a more expensive one, and the amount you can move is different in every house.
Last reviewed: October 2026
The saving comes from shifted kWh
Start with the amount of electricity the battery can usefully deliver each day. That is the lower of your usable battery capacity and the consumption you would otherwise buy at the expensive rate.
Multiply those delivered kWh by the price you avoid. Then subtract the cost of the electricity used to charge the battery, allowing for round-trip losses. Repeat that across the number of days you genuinely expect to use the strategy.
The five numbers that decide the answer
- Usable battery capacity in kWh.
- The kWh of expensive-period consumption you can actually replace.
- Your cheap charging rate or the value of solar electricity stored.
- The import price you avoid when the battery discharges.
- Round-trip efficiency, because you must put more energy in than you get back.
Without solar
A standalone battery relies on tariff spread. If the cheap and peak rates are close together, there is little margin to recover the installed cost. If the spread is wide and you have real evening demand, the arithmetic can look very different.
Put your own tariff into the home battery cost and payback calculator. It shows daily saving, annual saving and simple payback while making every assumption visible.
With solar
With panels, the battery can also store electricity that would otherwise be exported. The value of storing one solar kWh is not the full import price: it is the import cost you avoid minus the export payment you give up, adjusted for battery losses.
Use the solar calculator first to estimate generation, self-consumption and export. That tells you how much surplus might actually be available for storage.
What can reduce the saving
- A smaller tariff spread than the sales illustration assumes.
- Low evening consumption.
- Battery capacity that is too large for the daily load.
- Round-trip losses and standby consumption.
- A good export tariff that makes storing solar less valuable.
- Seasonal solar variation, especially if the calculation assumes summer surplus all year.