Tariff guide
How Does a Home Battery Work With a Time-of-Use Tariff?
Time-of-use tariffs charge different prices at different times of day. A home battery lets you buy electricity when it is cheap and use it when it is expensive, without changing your routine. This guide explains how that works in Scotland, what you need, and the questions to ask before switching.
Last updated October 2026
What is a time-of-use tariff?
A time-of-use tariff charges a lower price at certain times, usually overnight, and a higher price at others, usually late afternoon and early evening. Some have a fixed cheap window every night, while others change price every half hour. Several suppliers offer them, such as Octopus with its Go, Flux and Agile tariffs.
These tariffs need a smart meter that records your usage every half hour, so your supplier can bill you correctly for when you used electricity. If you do not have a working smart meter, your supplier can usually arrange one.
Tariff names, price windows and rates change regularly, so always check the current terms directly with the supplier rather than relying on an older comparison.
How does a battery save money on these tariffs?
The battery charges during the cheap window, then powers your home during the expensive hours. You use the same electricity, but more of it is bought at the lower price. The bigger the gap between the cheap and expensive rates, and the more you use at peak times, the more you save.
Most batteries do this automatically once the tariff times are set in the app. Some systems connect directly to the supplier and adjust themselves when prices change, which is especially useful on tariffs where the price changes every half hour.
This is why a battery can be worth considering even without solar. In Scottish winters, when solar output is low, tariff shifting is often the main source of savings.
Which tariff is best with a home battery?
There is no single best tariff. It depends on when you use electricity, whether you have solar, an electric car or a heat pump, and how much you export. The right choice gives you a long enough cheap window to fill your battery and a meaningful gap between cheap and peak prices.
Tariffs designed for electric cars often have a long cheap overnight window, which suits filling a battery. Tariffs with export rates that rise at peak times can suit homes with solar and a larger battery. Compare the overall annual cost, not just the cheapest rate, because standing charges and daytime prices matter too.
Are there any downsides to a time-of-use tariff?
If you use a lot of electricity at peak times without a battery, a time-of-use tariff can cost more than a flat rate. Prices can also change when tariffs are updated. A battery reduces that risk by covering your peak use, but it is worth checking your usage pattern before switching.
Some variable tariffs follow wholesale prices, which can rise sharply during cold, still spells. Fixed-window tariffs are more predictable. If you value certainty, choose a tariff with set cheap hours and compare how it would have worked against your last year of usage.
What else do people ask about batteries and tariffs?
Do I need a smart meter for a time-of-use tariff?
Yes. The supplier needs half-hourly readings to charge you the right price for each period. Most suppliers can install a smart meter for you. If you already have one that has stopped sending readings, ask your supplier to reconnect it before switching tariff.
Will the battery switch itself to cheap times?
Yes. Once set up, the battery charges and discharges automatically on the schedule you choose in its app. Some systems link directly with certain suppliers and adjust themselves when prices change, so you do not need to change anything day to day.
Can I use a time-of-use tariff without a battery?
You can, by moving things like washing machines, dishwashers and car charging to cheaper hours. A battery makes the savings much easier because it also shifts your everyday evening use, such as cooking, lighting and television, without you changing your habits.
Do these tariffs work the same across Scotland?
The tariffs are offered nationally, but prices can vary by region because network charges differ between areas. North Scotland and South Scotland are separate pricing regions, so check the rates for your own postcode when comparing tariffs.
Should I switch tariff before or after getting a battery?
Usually after the battery is installed and set up, so you benefit from the cheap window straight away. You can check eligibility and compare tariffs beforehand. Some tariffs require a compatible battery or smart meter, so confirm the requirements before committing.