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Do you know your cheapest time-of-use tariff hours?

Clock under lightening

About 3.9m UK households are on energy tariffs, which mean they get cheaper electricity at certain times. So you’d think it’s important to know exactly what those hours are to make sure you save as much as you can…

…but it’s not always an easy task.

Take Which? member Sue Hufton. The 58-year-old from Leicestershire thought her bills seemed high so decided to check the hours of her Economy 7 tariff.

She assumed a quick call to supplier Scottish Power would give her the answer.

But after numerous phone calls – and 39 days of watching her meter – she was still none the wiser.

She is one of a number of time-of-use tariff customers who have contacted Which? for advice on checking their tariff hours or meter clock.

The cheapest hours

Mrs Hufton said Scottish Power initially told her to contact her distribution network operator, which could not help. They then told her to call the meter manufacturer, which also could not help. Finally she said Scottish Power advised her to watch her meter to see when it changed over. She told us:

‘Over a period of 39 days, believe it or not, I kept a close eye on the meter around the time I thought that it may change over. I lost the will to live in the end.’

Mrs Hufton fears she could have paid more than she needed to by not knowing her cheaper hours.

Economy 7 generally offers seven hours of cheaper electricity overnight. But the exact hours vary between supplier, region and season.

Scottish Power apologises

After Which? intervened to help Mrs Hufton, Scottish Power said her off-peak hours were midnight to 7am GMT and 1am to 8am BST. A spokesman said: ‘We have contacted Ms Hufton and apologised.’

It has also sent Mrs Hufton some flowers by way of apology.

Ofgem says customers who can’t find their meter clock or suspect it is faulty should contact their supplier. But be warned – some charge fees if they are called out but then find the clock is correct.

Are you on a time-of-use tariff? And do you know your cheaper hours? Have you ever had trouble finding them out?


I have just rang Scottish Power and they have informed me that off peak hours for Electricity is 12:00 _ 7:00 all year round not the 1:00 _ 8:00 I was expecting for BST annoyed Steve

Maureen Mills says:
19 February 2019

It is virtually impossible to compare energy deals when you have an economy 7 meter and are all electric. Energy suppliers appear to vary their hours for economy seven across the country and without ringing each of them it is impossible to tell what they offer.

If you use Which?Switch as a comparison site, click “electricity” only, click “economy 7 meter”, put in your annual usage, % electricity used at night and that should give you a list of available tariffs that will include those offering day and night tariffs. It may well be no day/night tariffs are as cheap as a single unit charge as even if the night tariff is cheap you will pay a lot more during the day than for a normal tariff. It’s important you get your night time usage fairly accurate.