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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?


We have cheaper off-peak electricity so that heavy users can benefit from excess generating capacity overnight, when demand is lower. If meter clocks are set incorrectly, users may be using storage heaters and other high demand appliances when demand is high, meaning that more generating capacity is needed. All forms of electricity have an environmental impact and it is irresponsible for the suppliers not to keep meter clocks set correctly.

This is yet another example of incompetence by energy companies, who should be fined.

So long as the fines come off the profits and are not put on the tariffs I agree with you. There is absolutely no excuse for two-part meters not to be as accurate on time as they are supposed to be on Kwh used and the Regulator should require all supply companies to contract with their meter-reading agents to carry out a reliable time check every time they physically inspect a meter. Accurate time time recording might just persuade me that smart meters are a good idea.

John – I agree that fines should be paid for out of profits and not passed on to customers. It should be a requirement for fines to be reported in the Annual Report, hopefully with an indication of what action is to be taken to avoid future penalties.

I Googled “Scottish Power Economy 7” and it immedisately produced this very comprehensive document that gives nationwide tariffs, explains hours for white meters, describes how weather-adjusted heating is operated and so on.

That’s helpful Malcolm, and good of ScottishPower to provide this information. Some friends of ours [whom I mentioned in another Conversation about out-of-synch meters] had enormous difficulty getting their electricity supplier to give the hours when the night and day rates would operate in their apartment. All suppliers should be able to look up a meter number and quote the switch-over times [it was complicated in their case because they could not get access to the meter which was in a locked room in the block].

I note from the ScottishPower leaflet that ‘Night’ is formally defined as any period of 8.5 hours at ScottishPower’s discretion between 2200 and 0830 GMT, but in practice should be one of the following:
(a) 2300 to 0730 GMT (i.e. 0000 to 0830 BST in summer), OR
(b) 2345 to 0815 Local Time (i.e. same clock time all year), OR
(c) 0000 to 0830 Local Time at the choice of ScottishPower.
and that ‘Day’ means at all other times.

They’ve left themselves some wriggle-room so it’s still a good idea for Economy 7 consumers to ascertain the exact timings as well as check that the time-clock on their meter is both accurate and in synchrony with current time.

I was on Economy 7 for donkeys years, but as I’m slowly trying to reduce my usage, it got to the point that the standing charge on Economy 7 meant I was better off switching to a standard tariff.

If nothing I think the neighbours will probably enjoy the fact that I no longer run the washing during the night.

Alex M says:
21 April 2014

It’s not just the on/off times, are you getting the full 7 hours?
In addition to finding it difficult to obtain the on/off times for Economy 7, I also discovered that I wasn’t getting the full 7 hours lower price period, more below. Switching on my meter is by radio tele-switch. My supplier, OVO, told me to contact the local network management company who, when I eventually found out who it was, told me to talk to OVO. After several attempts I was given times but, unlike above I was told that the switching times were the same regardless of whether it was GMT or BST. I concluded that I didn’t really trust the information provided. Regarding the 7 hour low-price period and on account of the unwillingness of my provider to be clear about the on/off times, I wondered if they were less than honest about the full 7 hours. So, I did the following; I turned off all electrical power except for a one kilowatt heater which was switch on at 11pm and off at 8pm, taking meter reading immediately before and after this action, So, my nominal one kilowatt heater was on for 9 hours in which case my actual total consumption was a little under 9kWh. In this case, by starting at 11pm and finishing at 8am, I reckoned that 7 of the hours should be on economy 7, or 7/9ths of the total. Likewise the power consumption on economy 7 should be 7/9ths of the total. I divided the kWh on the low indicator by total consumption over the 9 hours to find that my Economy 7 was only active for under 6.5 hours. I repeated the experiment a few days later and recorded almost the same result. Now either the on/off times I was given (12 to 7) are very wrong or the power companies are selling us short!

David James says:
23 April 2014

Hi Brilliant articles in Which? last month and in the May issue on meters. I left a message for the team this morning with Emma and having spoken to Scottish Power a few minutes ago are updating you on progress. Like Mrs Hutton in your May page 5 article have been given the run around by Scottish Power (SP) – but unlike her I have made it known that a bunch of flowers will not help.
Thanks to your earlier article I checked the time setting on my meter and found it was running fast. I contacted SP and was given the run around – even given an incorrect start/finish time of economy 7. After a lot of persistence SP offered to change the meter but their contractor failed to show.
After more dialogue with SP an engineer called this morning and changed it, confirming that the old meter was running 45 minutes fast.
This is critical to the way we use cheap rate power – we have the washing machine and dishwasher on delay start/timeswitches set to run during the night but only use the tumble dryer when someone is around (fire risk). During winter months I usually load it at around 6.30am and run it for about an hour believing that this was within the “cheap” rate. But as the meter was 45 minutes fast and the “cheap” rate was supposed to be from 00.30 to 07.30 GMT the “normal” rate was actually commencing at 06.15 therefore the majority of the drying time was at “normal” rate rather than “cheap rate”.
I have spoken to a very helpful person at SP this morning who has taken all the details and promised to escalate the problem and call back later to let me know progress.
So, thanks for the original article pointing out the problem with meters – I will let you know progress.
David James,

My wife recently contacted my new supplier (OVO) to find out what the overnight timings were. They refused to give them to her stating that it would be a breach of Data Protection to do this as the account was in my name!!! They sent the timings to me in an email instead.
My points are:
1. Why are the overnight timings so secret? Why not simply publish them on the website?
2. How can these timings be a breach of my data protection since they do not contain any of my data?
3. Why not make the timings the same for all suppliers? That would be too simple wouldn’t it!

Oh…btw…for OVO the overnight timings are 0030 to 0730…just so you know. Saves you the bother that I had.

Donald M says:
1 June 2014

I’ve had this since my house was new in 1988 (from Hydro Electric/SSE) and still have the old mechanical clock, which has maybe slipped some 10 minutes over the years (but what I gain on the start time, I lose on the stop time). Anyway, to know the times, I can (1) look at the clock or (2) see the neon lights on my storage heaters or immersion heaters come on and off (at exactly the same time each day). I think (2) should work for most people. I can even hear the changeover when the house is quiet. The ‘problem’ seems to be over-stated.

Alex M says:
2 June 2014

I disagree with you Donald M. Many homes, like mine, do not have storage heaters these days. If they do, they no longer have to be “hard-wired” to the time switch and can be plugged into any power socket with the appropriate current rating. Similarly immersion heaters do not have to be “hard-wired” to the time switch. With this in mind, the function of the time switch is to switch whatever electricity you are using on any of your power sockets (washing machine, kettle, tv etc) from the day meter to the night meter. As such it is not possible by just looking at the appliance light indicator to tell whether the supply is on day or night rate. This is why it is difficult to know exactly the on/off times (especially if your meter is outside) and the real length of the so-called “7” hour period.

Similar problems with EDF. Phoneline always busy.
Tried emailing on 17 April 2014 and received the following useless reply:

– I understand your concern regarding the meter and would like to inform
you that the register 1 of your meter is for the day rate and the register
2 is for the night rate.

After several attempts to rephrase my question, received the following:

– The start time for the cheaper unit rate is 10:30pm and ends at 07:30am.

Sent 2 further emails asking whether GMT or BST but they do not know what these are. Am still waiting for a reply (early June).

Jean Hart says:
7 March 2015

I have been a Scottish Power customer for 3 years.Over the last few days I have had two phone conversations with different Scottish Power employees regarding my economy 7 electricity meter. The first one, Kath, agreed, after I had explained the times that I used the most electricity, that economy 7 was not my best choice, money wise, and there should be no problem with SP replacing the meter with a standard one. She said she would ring me back a few days later regarding replacement arrangements. She didn’t, so I rang again and spoke to Tony, who said that Scottish Power did not allow call backs of the nature Kath had arranged and that SP would refuse any request to replace my meter. He also said that Economy 7 was not about saving money – “it was not called Economical 7′” I also asked what my off peak hours were, and, after being put on hold for ages, he said he couldn’t find this information. I told him I was most unhappy about getting conflicting information from two SP employees. He did not comment on this. If this conversation was recorded “for training purposes” it should definitely be used on how NOT to deal with ‘difficult customers’

Jean, try using this email to Scottish Power dirsupp@scottishpower.com to voice your complaint and ask for the information you need.

Borders Granny says:
15 April 2015

I have the same problem as people above, I am happy to set various appliances to come on in the night, but there is no definitive time span given anywhere as to what their “discretionary” 8.5 hours actually means so cannot be sure when i am on “night” rates other than to assume that by about 2am they will have got their act together.
Just another example of their deviousness and lack of awareness of their customers’ needs. There is no way I am going to try contacting them – when they do phone you about something the call registers as their general helpline so you have to queue and then start the whole conversation with another operative. It has taken me 3 months to get an electric bill out of them (yes, I had to pursue them for it!) after realising they had not been taking the direct debit arranged last June when we moved. That’s without mentioning the updating of my meter which they are also apparently unable to organise even with my MP kindly taking up the case as well. Apparently they are going to credit me with £50 once they sort the meter which hardly compensates for the time and cost of hours on the phone, emailing and the stress they have caused!
I had intended to try for dual fuel with them, but will be switching supplier once they sort out the current issues and doing it through …. well … anyone else, really!

I am totally confused regarding Economy 7, which I have. I have a large water tank with two switches, one has a label “water” on it and the other “night”. A neighbour advises me to leave the “night” switch on all the time, as the water is heated on the overnight cheap rate, but if you use water during the day, surely the replacement water is reheated and consequently uses the day rate? Can anyone explain what I should be doing?

If you think that’s hard, try persuading NPower that when they changed the meter, they input the readings incorrectly, putting the old night rate meter readiing into the day rate and vice versa. How they are going to work that one out I don’t know, but they aren’t getting another penny till they do. If they gave me the date of the change I could do it for them, like we have to do everything for them these days. My account is closed, now with SP (mmm) so we’ll see how it goes.

Geoff says:
8 August 2016

Hi all,
I am having a nightmare trying to obtain the time for my area when economy 7 starts and ends, British Gas say it is the Network Supplier, the Network Supplier say it is British Gas.
Has anyone got an idea who I can call for this information. If I ask the question regarding how much do I owe they have an imediate answer but can’t sat how it was calculated.
Look forward to a response

antonio mucedola says:
3 October 2016

I would like to know from what time to what time the economy 7 start and finish
i have a time clock and needs setting .

You should contact your electricity supplier, Antonio, as the times differ from company to company and in different areas. You will need to have your meter number to hand when you speak to them as well as your electricity account number. Your latest bill should have this information on it.

Round says:
14 October 2016

All electric providers should have the same economy 7 times and they should be clearly stated so customers can take advantage of cheap rate electricity and not get caught out by not using it when they think they are

It seems that, depending on supplier, or location, or both, Economy 7 starts at 23:00, 00:00, or 01:00. I cannot see the need for all electricity suppliers to have the same hours for Economy 7 provided (a) that they ensure that the meter time is set correctly and adjusts automatically when the clocks go forward and back, and (b) that they state the times clearly in their contracts and on customer bills. Ideally they should also provide a label to go on or next to the meter. When customers change to a new supplier they need to check the Economy 7 times and have the meter adjusted if necessary. In some properties certain circuits [such as for water heating or storage heaters] have their own time switches and they should be synchronised with the meter timings; this can usually be done by the customer.

The reason that not all companies need to have the same start and finish times for Economy 7 is that the overnight demand profile differs between companies and since the scheme is intended to be an incentive to use off-peak electricity at times when generating capacity is available a standard time might not be acceptable. The Economy 7 unit price for electricity also differs between companies so the choice of supplier can also depend on the balance between daytime and overnight consumption – just another dimension to add into the complexity of choosing the best tariff.

It is especially important to get the start time in line with the supplier’s time for water heating and storage heaters because maximum power will be drawn after the initial switch-on to bring the water temperature up to the set level after the day’s use and to recharge the thermal storage in the convection heaters.

This comment was removed at the request of the user

The only reason there are so many solar panels on residential property is that they have been heavily subsidised from the outset. It is noticeable how few commercial or public service buildings are fitted with solar panels. Did the research paper have anything to say about the growing number of solar panel farms cropping up all over the countryside? For the last few days I guess they’ve delivered nothing. Not an attractive investment.

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Thanks Duncan – I thought that would be the case. For the next six months [the colder seasons when heating is required] solar panels don’t get going until around 10:00 and then the inclination of the sun is not favourable . They can’t contribute much after 16:00 even on a sunny day. I cannot understand why so much money, time and energy (!) has been expended on this unsuitable development for the UK which has adverse environmental consequences in terms both of the initial manufacture of the PV panels and the related infrastructure, and of the despoliation of the natural environment.

With regards to solar panels on residential properties, it is not fair that hard-up people are having to continue to subsidise through their taxes and electricity bills those who could afford the initial installation and now receive a premium over the tariff rate for feeding in to the grid. [Before someone says hard-up people don’t pay much in taxes I would remind them that we all have to pay VAT on purchases (including electricity bills) and duties on various products that bear more heavily on poorer people and those on fixed incomes.]

just rang scottish power .They replaced a mechanical 2 rate meter with a clock with a digital meter no clock in june 2016 usage seemed wrong so i checked .They fitted it and transposed the day night meters being honest i told them about it a month later no response . i rang again they the said they can only fix it by changing the meter . i asked what are the hours it operated the said 11 pm to 6 am i said thats not correct the still don’t know when the meters change .I am taking my time allowing them to set the timetable as i am being charged rates in my favour .They didn’t turn up to fit the first meter as they lost the booking so they will probably get it wrong again and it took 6 hours of complaints to get a new date less than 4 weeks away so i.e. expect a timetable of 2020 is probably right .i have asked for a 2 rate smart meter they said they cannot fit one but they hope to do it by 2020 . i asked can i continue with paying the economy 7 rates the wrong way round till 2020 as a good will gesture , i have had no response yet about the offer or a offer of a working meter smart or otherwise.

L.Esposito says:
27 January 2017

Power cuts can upset these meters too, get a twelve hour difference! I shouldn’t worry!