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Some of us with old, ineffective night storage heaters may have decided that, the price of electricity being what it is, there are better ways of keeping warm. If the heaters aren't being used, or used as much as they once were, it may be that the higher unit rate for peak-time usage means that an Economy 7 tariff may be more expensive overall than a single-rate plan. This post may help you decide.

You will need to know how your current electricity consumption is split between peak and offpeak periods. The last six months usage should give a fairly good indication, so now in February:

  • Find your bill for last August, or look it up online. Make a note of the peak and offpeak meter readings for the beginning of the period, e.g. 1 August.
  • Find the same figures on your bill for last month (January), this time taking the readings for the end of the period.
  • Subtract the peak reading for August from the one for January to find the peak-time consumption for the whole period. Similarly, subtract the offpeak reading for August from that for January to find the offpeak consumption.
  • Add these two figures together to get the total consumption for the period.
  • Divide the offpeak figure by the total to find the proportion of consumption attributable to offpeak usage. This should be a number between, say, 0.10 and 0.90, but will in most cases be closer to 0.30. We'll call it P.

Now find the two tariffs you want to compare. Visit Our plans & prices to see all those available for your location, meter type (multi-rate) and payment method. You should see some Economy 7 plans where one is the one you're already on, and another under the same heading (e.g. Simpler Energy - 01/01/2024) where the Unit rate (peak) and Night unit rate (offpeak) are the same. Make a note of the three rates. We'll call them a, b and c, where a and b are the different peak and offpeak rates while c is the single rate. We'll ignore the difference in standing charges for now, because it's probably immaterial.

Back to your calculator: work out (a-c)/(a-b). The result should be somewhere between 0.30 and 0.45. We'll call this number Q.

If P is less than Q, Economy 7 isn't right for you. If P is bigger than Q, Economy 7 is saving you money.

If P is only slightly less than Q, you might be able to save by shifting more consumption to the offpeak period. This could be running power-hungry appliances like tumble dryers, dishwashers and washing machines overnight. You could use cheap clockwork time switches (e.g. these ones at £15 for 3) to start them half an hour after the offpeak rate kicks in, or if you know how long they run for, to make sure they're finished before peak rate starts.
  

An example from my own figures:

 

Readings:

1 August        Peak                6977
1 August        Offpeak        10500
31 January    Peak                7492
31 January    Offpeak        10745

 

Peak usage 7492 - 6977 = 515
Offpeak usage 10745 - 10500 = 245
Total usage 515 + 245 = 760
P = Offpeak/Total 245/760 = 0.3224 

 

Rates:

a = Unit rate                27.46
b = Night unit rate      18.24
c = Single unit rate     24.42
Q = (27.46 - 24.42)/(27.46 - 18.24) = 0.3297

 

I'm right on the limit, so it makes little difference in my case. This means, though, that I should keep a careful eye on the next price change (due 31 March) and do the comparison again. If it's changed in my favour, well and good. If it's gone the other way, I should consider asking for my plan to be changed to single rate.

 

UPDATE 26/04/2024: This NB is apparently no longer true:

>NB Sadly, if anyone has done this (changed from Economy 7 to single rate), it's irreversible. The only way to go back to Economy 7 currently is to have a new meter installed, and if that's possible, it may not be free.]

See this post:
 

 

/If anything isn't clear, please reply to explain what.]

 

This is a really helpful topic @Firedog.

 

My dad has old night storage heaters, and two separate meters. I’m going to send this topic to him to have a read of. 

 

He’s toying with the idea of getting one of the meters removed so that he only has to pay one standing charge, and overhauling the heating system. To make matters more complex the supply was listed as commercial for a long time, as his home is a converted building. 

 

Will let you know how the situation progresses!

… and I thought you were an expert on archaic, esoteric metering arrangements 😉

Just for future reference, what’s the procedure for changing from a business to a domestic account? I’m sure it’s exceedingly complicated and takes many months ...

My OP should really be an article. It’s not supposed to be a discussion, nor is it an idea, and despite its title, I don’t think it’s a question within the meaning of the act. I think someone with a big stick has to agree. If you fall over him/her, perhaps you could arrange for the move. If it happens, that would a good time to remove this OT post 🙂

At OVO, we do not supply commercial properties. If a customer has a Profile Class 3 or profile Class 4 listed on ECOES (the national database), and they wish to sign up with OVO if it’s a commercial property they won’t be able to sign up with us. If it’s a domestic property, wrongly listed as domestic, the customer will need to get this corrected on ECOES with their current supplier before they switch to us, as the switch should fail as we do not supply any Profile Class 3 or Profile Class 4 MPANs.

 

If a customer on supply with us is incorrectly listed as having a commercial account we’d raise this internally to our metering team to get this updated with ECOES, the timeframe is dependent on the timeframe for ECOES (as they’re a third party we’d be reliant on). 

 

P.S My dad is with EDF, will let you know how his situation compares. 

Hi @Firedog 

Just noticed this topic (linked from your reply a few days ago).

You mentioned 

NB Sadly, if anyone has done this (changed from Economy 7 to single rate), it's irreversible. The only way to go back to Economy 7 currently is to have a new meter installed, and if that's possible, it may not be free.

 

Is this really so? I thought with a smart meter you could choose the tariff? When I was with BG and had an old dual rate meter they switched me to single rate (simply by adding the two readings together).

When I moved to OVO and had a smart meter fitted they reverted me back to dual rate. Since I used around 29% of our electricity off peak I didn’t think it was worth the hassle of changing back to single rate so I didn’t ask. 

That’s a good point @BeePee I’d forgotten that my meter used to be economy 7; OVO changed it for a smart meter years ago and moved me to a single rate. Then last year I switched to Octopus and now I’m on one of their TOU tariffs, Go, which requires an EV.
Is the inability to return to E7 because it’s an archaic tariff rather than a modern shiny one ? I remember mine being a right pain as it was split 2 hrs low, 2 hrs high, then 5 hrs low. The hours moved with the clocks changing so I had to have a chart on the wall to remind me which way to switch the immersion timer every 6 months. Thank goodness that’s all a distant memory.

  

Is this really so? I thought with a smart meter you could choose the tariff?

 

Well, this hasn’t been updated since July 2023, but I haven’t heard of any change. Perhaps @Emmanuelle_OVO could confirm for us that there’s been no progress in this respect.

You might remember that the billing platform at OVO is the limitation which restricts the move from single rate to multi. 
I don’t fully understand with the 30 minute data capability but perhaps there needs to be a significant change in the construction of the data within billing to allow the changes needed

I don’t understand the difficulty either. However, I don’t think half-hourly data have anything to do with it. E7 meters have two registers, and its the advance of these registers that provides the usage figures for billing. Of course, the meter has to be configured to switch register at the right times, but assuming that that’s in order, I can’t see why it’s so difficult just to apply the appropriate tariff rate to the readings the meter returns. I wonder if @Emmanuelle_OVO could add that question on if and when she gets through to someone who could answer it.  

 

When I was reading around this I found this

Economy 7 meters & tariffs: How to max your savings - MSE (moneysavingexpert.com)

See section 4 and expand the Which suppliers let you switch to/from an Economy 7 meter? section.

Apparently OVO can switch either way for free!

Updated on 01/05/2024 by Shads_OVO

Hey @Firedog,

 

The information on this thread is still valid. Unfortunately, we don't currently have the functionality to change smart meters from multi rate to single rate or vice versa. But, if someone does get in touch to request a change from multi rate to single rate, what we can do is offer the them a change of contract. The customer will essentially be charged the same unit prices on both rates, the peak and off peak. This means that they are being billed for the same unit price regardless of what time of day they use their energy.


If they're already in the middle of a fixed tariff, we'll swap them onto the other version of their current plan, rather than starting again from scratch. 

 

There’s nothing ‘unfortunate’ about that. I’ve been through this process myself, so I have the distinct advantage of seeing how my usage pattern is split peak/offpeak, which means I can work out easily whether E7 would be worth it or not. There’s no change at the meter*, so the registers swap from peak to offpeak at the same times as before and two sets of readings are conveyed to OVO as before.
 

*   … apart from the tariff data, that is. I suppose that these are passed to the IHD, so are necessary if the IHD’s cost figures are to be helpful. Otherwise, they don’t have any significance (except for PPM customers, of course, for whom it’s vital that they’re correct). 

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