Understanding your off-peak times
What are my off-peak times?
Your off-peak times depend on your tariff and you'll find them in your welcome pack. They're always set in UTC, so on a UK clock they're the same as shown in winter (GMT) and one hour later in summer (BST).
For example, if your tariff's off-peak times are 00:00 to 05:30 UTC, that's 00:00 to 05:30 on your clock in winter (GMT) and 01:00 to 06:30 in summer (BST).
What is UTC?
UTC stands for Coordinated Universal Time, the fixed time standard used around the world to keep clocks and computer systems in step.
UTC never changes, which means it's the same as UK time in winter (GMT) and one hour behind UK time in summer (BST), when the clocks go forward.
Why don't my off-peak times follow the clocks?
Every half hour, your smart meter sends us a reading of your electricity use in UTC, which we use to work out which of your electricity was used at the off-peak rate.
Because UTC never changes, your off-peak times stay the same in UTC all year. On your clock, they move an hour later when the UK clocks go forward in March and return to the times shown on your tariff when the clocks go back in October.
For example, a 00:00 to 05:30 UTC off-peak window runs from 01:00 to 06:30 on your clock in summer (BST).
Do I get fewer off-peak hours in summer?
No, you get the same number of off-peak hours every night, all year. They start and end an hour later on your clock in summer (when the UK moves to British Summer Time), but the window is the same length.
Setting up your charger and appliances
What should I set my EV charger to?
You have two options:
- Set it once and forget it: schedule charging to start one hour after your off-peak start time and finish at your off-peak end time, which fits inside your off-peak window in both summer (BST) and winter (GMT) so you never need to change it. For example, on a 00:00 to 05:30 UTC tariff, set your charger to 01:00 to 05:30.
- Get every off-peak hour: use your off-peak times as shown on your tariff in winter (GMT) and add one hour to both the start and end times in summer (BST). For example, on a 00:00 to 05:30 UTC tariff, that's 00:00 to 05:30 in winter (GMT) and 01:00 to 06:30 in summer (BST). You'll need to update your charger on the day the clocks change, twice a year.
Is it a problem if my charger or car app uses UK clock time?
No, but you need to account for it, as most chargers, cars and apps follow the UK clock and change automatically when the clocks go forward or back. Your off-peak times don't, so in summer (BST) add one hour to the start and end of your schedule or use the set-and-forget option above.
Some smart chargers let you choose a time zone for your schedule or already know how your tariff works, so it's worth checking your charger's app or manual.
When the clocks change
When do the clocks change?
The UK clocks go forward one hour on the last Sunday in March and go back one hour on the last Sunday in October. The next changes are:
| Date | What happens | Your off-peak times on your clock | Example: 00:00 to 05:30 UTC tariff |
| Sunday 25 October 2026 | Clocks go back | As shown on your tariff | 00:00 to 05:30 |
| Sunday 28 March 2027 | Clocks go forward | One hour later | 01:00 to 06:30 |
| Sunday 31 October 2027 | Clocks go back | As shown on your tariff | 00:00 to 05:30 |
What happens on the night the clocks go back?
At 01:00 the clocks go back to 00:00, so the hour from 00:00 to 01:00 happens twice, but you still get your full off-peak period. For example, on a 00:00 to 05:30 UTC tariff, off-peak runs from the first 01:00 until 05:30 on your clock that night.