I have two electricity meters with two MPANS - Why are my storage heaters resulting in high energy costs?

  • 7 September 2021
  • 27 replies

Userlevel 2


I have browsed the forums here for a few days now and found some very informative threads (the staff and community seem really helpful and knowledgeable!) but I still wanted to make a post asking about my specific situation.

I wanted to post here before applying to switch, as last year I tried to switch to two different companies (Bulb and SSE) and both moves fell through. After all the time and effort I put into working out what was going on with my set up and trying to get a decent deal, I reluctantly gave up and stuck with my current provider, but I’m going to try again this year before winter hits.

I am a private tenant, currently with EDF but would like to find a company that can offer me a better tariff to go with the somewhat ancient and expensive electricity and heating set up in my rented flat in Scotland. The flat has no gas supply, and is heated by one main storage heater and two smaller ones, though I have only ever used the main one. There seems to be two electric meters (with two MPANS): a H00C17109 “Horstmann radio telemeter series 2a” and a 7411577 "English Electric" meter (I will post photos below). The Horstmann reading ticks up negligibly when I have the storage heaters turned off, but when I had the heater turned on in the colder months, it racked up bills like I’d never seen before. During the winter months, I was seeing monthly usage readings of over 1000kWh and bills of £120 just from the one storage heater on the Horstmann meter, not including (albeit the much more manageable ~£30-40) English Electric meter usage costs, which I assume covers all the other electricity I am using. As I have been on long term sick leave, bills of over £160 per month for electricity this winter are going to be really difficult to pay. Frustratingly, the house still only reached a temperature of 16 degrees last winter with the main storage heater on all the time, which was barely manageable, but I couldn’t afford to turn any of the other heaters on.

EDF have me on a tariff that doesn’t seem to take advantage of off-peak energy and they cannot or will not put me on one. Instead, the Horstman meter is on what I think is a low rate (13.65/kWh) without a standing charge (as I pay one on the other meter) but I still wonder if something like Economy 7 would be better, even if slightly, as I realise that storage heaters are expensive to run in general. Not sure, but I think the reason they can’t put me on that is because I have two meters. I’ve been on the waiting list to change to a smart meter for a year, but it hasn’t happened yet.

So.. my questions.. (sorry if I’ve overexplained the background!)

After reading around on here, it seems that OVO may be able to switch me over and fit a new meter (5-terminal SMETS2?) and put me on a suitable tariff. Does anyone know if I can do that, and how I would go about it? I really worry about being moved to OVO, and then not being able to get a cheaper tariff because they aren’t able to move me to a new meter system for whatever reason. I read that there was some kind of billing issue that made this not possible, is that resolved now?

Also, it would be helpful to know if I would need to pay for an electrician myself, as then I would need to see if the landlord would be willing to cover the costs, and I know how that usually goes. I am also going to look into the possibility of getting my landlord to agree to buying more efficient storage heaters as I think they can be subsidised, but I’m not holding much hope.

I’ve attached photos below of my set up. I know I have two MPANs from previous conversations with EDF, but I have received conflicting advice about how these meters are working - either as two completely separate devices with two separate circuit systems for the heaters and for everything else, or as some kind of interdependent system where one meter ‘tells’ the other to turn on and off or switch rates. I suspect it’s the former given I pay bills for both meters but radio telemeter meters are commonly used for the latter?

Any advice to send me down the right track much appreciated! 



I can take a photo of behind the wooden part next to the English Electric meter if needed. 



Best answer by BrightEyes161 2 October 2021, 00:53

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27 replies

Userlevel 2


Been a while but thought I’d update. They changed the meter, it is done! Not sure how it’s affecting my bills yet, but at least we know it’s possible to do now.. with a lot of research and fighting..

Funnily enough, after the meter was changed, my landlord said they’d send someone over to see if i can get gas..

Userlevel 7
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Ok, I think I’ve got a bit of an idea of what’s going on here. Thanks for the detailed description, you probably have no idea how helpful that is to us and this is absolutely brilliant. We can definitely try to figure something out here without you having to commit to any recommendations.

I’d also like to assure you that you will not be committed to doing anything (such as switching to OVO) purely because you came here to ask for help and it’s all offered completely free of charge. We like to try and give you advice that helps you out no matter which way you ultimately decide to go.

I’m going to need some additional backup here, so I’ll call in @Tim_OVO and @Jess_OVO to get some advice on whether OVO can take on your supply - or what you’ll need to do first before you can switch. I know it used to be difficult for OVO to take on supplies with these complex meter setups prior to the complex meter being replaced with something else, but things may have changed since. The Dual-MPAN has previously been a choke point, but I’ll ask to see if OVO has managed to make any progress towards supporting these.

I’m struggling a little to identify exactly what you’ve got, but it appears that you might have some kind of Economy 7/White Meter configuration (Economy 7 is often referred to as White Meter if you’re in Scotland). But it’s more complicated than that. Something gives me the feeling your meters are actually set up for SSE’s Total Heat Total Control tariff, which is a legacy tariff type that’s no longer available. And THTC meters are really complicated setups!!! Even now I struggle to fully understand THTC despite spending several months reading through documentation about it!

When I think about this more deeply, I begin to become more convinced that this a THTC setup rather than an Economy 7 setup. I can’t find any traces of EDF offering anything similar, but it might be because they’ve removed all the references from their own website or just buried them so deep that I can’t find them.

(Edited in afterwards, I think the tariff in question might have been EDF Warmwise in this case, but I can’t say for sure).

One of the other headaches is that complex meter setups like THTC used to be tariff-specific, making switching supplier almost impossible in some cases. It sometimes even made it impossible to switch tariffs with the same supplier too. From my understanding, going from THTC to E7 is also a bit of a challenge, since there’s no way to reconfigure a traditional meter without a Meter Exchange - and this is rarely as simple as you might think for these scenarios.

Unfortunately, once you come off these legacy tariff types, you can’t go back on them at all - this is probably why EDF is refusing to switch you back to that off-peak tariff you were previously on. The only exceptions are Economy 7/White Meter and Economy 10 which are still available. They’re primarily offered with Smart Meters these days, but I think they can be provided under traditional meters in special circumstances - such as if you switch supplier with the existing meter already being Economy 7/10/White Meter. It’s possible that some of the legacy complex tariffs still exist in a new form (such as Time-of-Use) but I think most of the ones that required complicated meter setups have been dropped these days. And any changes you make to the meter setup will almost certainly impact your heating and hot water.

As for the way forwards, this is a bit of a tricky one. You’ll almost certainly need to have a fair amount of work done if you’d like to migrate to Smart Meters - and this could involve a fair amount of rewiring that a local electrician will need to do for you, to make sure everything still works. If you’re still using Storage Heaters, then Economy 7 is probably your best bet for the time being, unless you manage to find a Time-of-Use Tariff that can precisely match your needs (but you would be taking a bit of a gamble with those). All of OVO’s tariffs can be taken with the Economy 7 option as well. An S2 Aclara SGM1412-B or Aclara SGM1416-B for example, are definitely capable of managing Storage Heaters no problem as they both have built-in capability to switch Storage Heaters on and off at the right times. OVO can definitely install one of these meters, but the problem here is more about handling the existing setup…

Let me borrow @Transparent as well. He might have some advice regarding any potential rewiring work. I strongly recommend getting your landlord to help you out as well, since you’re in a rented flat and their consent is probably required. Most landlords are usually OK with this but it never hurts to ask first.

I hope this helps. We’ll be happy to answer as many questions as you can think of.

Userlevel 2


Thanks for all the advice again.

The situation with the DCUSA Schedule preventing this going forward seems complicated. I do wonder why that agreement is in place, and from what I read it appears to be to do with the limitations of the distribution grid. There is only so far I am willing to go down this research rabbit hole though, as it’s definitely got to the point where it seems out of my control.

So I’m at the stage now where I think you’ve given me all you can for now - thanks so much again. Hoping this thread is useful to someone else down the line.

I have sent emails about tariffs/storage heaters/energy efficiency grants to various places and I am currently awaiting responses from

  • CAB
  • Landlord
  • SSE
  • EDF Complex Meters team
  • EDF Warm Homes scheme
  • Grants schemes, esp. Home Energy Scotland 

and will call if no response.

If it is useful, you can keep this thread unlocked and I can provide updates with what they say?

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Ouch, that’s really not good news then.

Clearly, EDF haven’t heard of this great company called Aclara either. Last time I checked, Aclara was offering an S2 Aclara SGM1416-B Five Terminal Smart Meter which definitely is five terminals and is definitely SMETS2 so is a Smart Meter - and is one of the models that’s commonly deployed to replace most types of traditional five-terminal meters. I don’t think most other meter brands have one at this time that I can think of. But even then, the DNO restrictions makes Economy 7 impossible for your area right now, so that’s not currently an option. I just wish EDF would recognise that 5 Terminal S2 Smart Meters do exist, even if they don’t exist from the brand that they’ve gone with. OVO uses Aclara for S2 though, so if it wasn’t for you being in Scotland, it could have worked.

This is a really, really tough call to make and I genuinely feel your pain here. I really don’t like to make suggestions like this for reasons that I think you can understand… But it seems like switching to gas heating might be one of your only options. It’s not something I’d normally recommend because it kinda goes against the idea of de-carbonising the grid but sadly the reality is that there are still cases where electric heating isn’t always practical and this feels a bit like one of those edge cases. I’m concerned as well that given where you are, losing that much heating is going to basically turn your flat into an ice cube. You’ll likely need to chat with the landlord about this first, since it could require a lot of work to set it all up.

Userlevel 7


Interestingly, they also said that “a 5 terminal SMETS2 Economy 7 meter is what you would need because of your storage heaters, however they are not available in Scotland at this time” and “The only other meter type we can offer you is a 5 terminal legacy Economy 7 meter (not SMART at present) which would give you 7 hours of cheaper usage overnight.” 


We’re a bit surprised to hear this, @BrightEyes161  - depending on exactly where you are in Scotland the limitations in switching away from your current set-up to an Economy 7 meter would still apply even if the meter was traditional rather than smart. This might be worth double-checking with EDF, who can confirm whether you’re within the ‘Load Managed Area’ which is affected by these limitations.



Maybe just staying with these meters and seeing what tariff they can give me now is best.. Though as I said earlier, the one they originally offered has apparently expired. What a mess..


That’s really frustrating to hear - whilst we can’t comment on other suppliers policies, any tariff offers OVO send out via email would be guaranteed for 7 days from the date the email was sent. It might be worth giving EDF a call to check this point, I’d have thought they should allow you time to consider your options before you settle for a plan.



But it seems like switching to gas heating might be one of your only options. 


Obviously this is quite a big and costly decision (for your landlord to make) and it would depend on whether your home is on the gas network (there are areas in Scotland which aren’t supplied by the gas network). Again it might not be the news you wanted to hear but just wanted to make sure you’ve got all the information before you consider your options.


As ever, keep us posted on any further developments - we’re interested to hear the outcome for you. :slight_smile:


Userlevel 7
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Hey there @BrightEyes161 ! Welcome to the OVO Forum! :)

This is just a quick heads up to let you know that I’ve acknowledged your question. It’s a pretty long one, so it’ll take me a while to read through the entire post. I’ll post another comment once I’ve had a chance to read through everything, but if there’s anything else you can add such as more photos, please feel free as they really help us out!

Speak soon! :)

Userlevel 2

Hi! Thanks so much for the reply!

And thank you for the reassurance - my main worry is switching under the impression that I can get a tariff (and meter if needed) that works better for me, and then being told afterwards that I can’t. This happened with another company (I think they didn’t realise exactly what kind of set up I had) and, even though the switch didn’t fully complete, it was a hassle to sort out, which is why I wanted to check here first about what is going on!

I think the dual-MPAN and complex meters ‘brick wall’ you mentioned is what I encountered last time I tried this too - my current provider have yet to fit me a smart meter, and new providers are hesitant to take me on with this old set up, or tell me straight that it would be very expensive, so I’m stuck with an old set up with a company who have given me a seemingly ‘best fit’ tariff that may not be ideal. And being a tenant, I don’t want to spend a large amount on an electrician to fix the wiring myself, so would definitely be asking the landlord to cover that if it isn’t covered in the switch.

Thanks for the rest of the info too. Seems complicated.. and seems the meters are way past their recertification date! I wonder if the landlord would take this into account should I need to ask about them paying for an electrician. The rental agency, who I rent through on behalf of the landlord, did say that the meters were a ‘white meter plus a standard meter’, but I not sure if they know for certain, and they didn’t know any more than that. It does seem like the case that the meters were set up for something that no longer exists, or is really hard to find..

I’ve attached a couple more photos too - one of the breaker below the English Electric meter, and one of the wires behind the area that was covered by the wood (in between the meters). Not sure if useful, but gives a more complete picture.


Edit: I do have access to my MPANs too if useful.




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No worries. You’re clearly experienced in having to deal with this and I can totally understand the headaches you’ve been through. That’s precisely why this forum exists. I’d much rather you get the right advice upfront (even as a forum volunteer!) before you hit another brick wall, than to take a gamble into the unknown and probably fail again. I’ve got a guide that will also help too. Here you go. Technically speaking, any references to “you” also apply to the landlord to at least some extent. If they’re ever unsure about anything, please let them know they’re more than welcome to stop by the forum as well and we’ll be happy to help.

It’s also not surprising at all that hardly any supplier is willing to take you on. These complex meter setups cause serious nightmares and even OVO has choked a few times in the past. I’m hoping Tim and Jess can get an update on whether OVO can support these setups either directly, or by going via SSE for now (OVO now owns SSE’s retail division).

I would be willing to agree with your rental agency as well. Personally, I think they’ve given a pretty reasonable guess and it’s probably either E7/White Meter or THTC/Warmwise. The thing that makes me ultimately think it’s SSE THTC is the fact that SSE is referenced on the RTS Meter (that’s the Horstmann one). We’ve handled similar questions a couple of times, so I’ll give you these threads as they might be of interest. But I wouldn’t be surprised if your setup really is White Meter/Economy 7. It just seems a bit unusual to have used that model of Horstmann RTS Meter for E7 purposes, when they’ve been more commonly seen for THTC...

With that being said, you’re probably right in scope of SSE Energy Networks (SSEN) as your Distribution Network Operator (DNO) because I think they do most of Scotland. Unlike SSE Energy Services, SSEN is still part of the SSE Group. I just can’t picture SSE or SSEN installing that meter on behalf of EDF somehow…

What I can definitely say, is that the meters you’ve got are pretty much never installed anymore outside of maybe a few rare edge cases - and usually just to replace existing like-for-like setups. And they were for legacy tariff types that are definitely going away. Complex tariffs were never exactly good value and generally caused more nightmares than they solved. The vendor lock-in issues with not being able to switch suppliers are just the start...

The delays in getting your MEX done might be down to a huge backlog combined with the fact you’ve got that dreaded complex meter setup. It’s only recently that Five-Terminal SMETS2 Smart Meters became available and even then, there’s the added complication of sorting out that spiderweb of wiring. And yeah… This won’t exactly be cheap either.

I really hope this can get sorted out though. As much as I’d love to have said that you could switch to OVO and then have OVO take care of the upgrade for you - which works fine for 99% of cases where the metering setup is nowhere near as complicated - complex meters are a completely different beast that needs more special attention. That’s why I’m hoping Tim and Jess can get some more details from the teams who know more about how it works.

It might be worth looking at replacing those Storage Heaters with something else in the future, but you’ll probably want to discuss that with the landlord first. Even if you just replace them with newer models that are more energy efficient, it might bring the bills down. I think it’s also possible that you might qualify for the Warm Home Discount as well. If you do qualify, it’ll give you £140 off your electricity bill to help you through the winter - and it’s available with almost all suppliers including OVO. Some of the smaller suppliers might not offer it though, so I definitely recommend asking first before switching if you plan to make use of it.

Userlevel 7

Hi @BrightEyes161 and welcome to the OVO online community,


Firstly just wanted to say I totally emphasise with your situation - these complex meter set-ups are really tricky in terms of switching suppliers and knowing you’re getting the cheapest rates to keep your storage heaters running through those cold Scottish winters.


Our community volunteer, @Blastoise186, is all over it with the great advice. From my understanding of things it does look to be a Total Heat Total Control type setup - but I’m going to take this one away to our team of experts to check if that’s the case and if so what the options are in terms of a switch to OVO and a smart meter upgrade.


It’s definitely worth getting in touch with your landlord to check the efficiency of your storage heaters as by the sounds of it, you’re already using energy at off-peak rates to get these charged so just a change to the meter or plan might not be enough to bring the costs down. I’ve had a little scout around for some relevant advice in getting the most out of the current set-up and would really recommend giving the Centre for Sustainable Energy’s (CSE) storage heater guide a read - They’re a charity we partner with who can give some really great impartial energy saving advice.


Have EDF confirmed what type of tariff you’re currently on and why they’re not able to offer you a smart meter yet?


Hoping some of this advice is helpful - do keep us posted with any further questions. We’re always on hand here to offer advice where we can. :slight_smile:


Userlevel 2

Thanks so much for all the advice and the links @Blastoise186. I’ve opened them all for some evening reading and will reply more if I have something to bring up!

Related MPANS does ring a bell though from when my switch failed before, actually. Although I think it would have been able to go through with SSE or Bulb if I had continued, after they fiddled with the system. But one of them (I can’t remember which) called me to say that it would be really expensive, as they can’t really give me a suitable tariff, almost certainly for the reasons you said earlier. I can’t really remember why I didn’t do the switch with other, but I have a feeling they might have just not let me switch full stop.

Regarding the confusion between white meter/e7 and THTC, do you think that it was originally designed for and was on a THTC tariff with SSE, but before I lived here someone moved over to EDF and that’s why it is a weird fit? What you wrote about SSE changing the control signals based on the weather may also explain why on some days when I had the meter on, the house was way hotter than I feel it should be, if it is no longer weather dependent due to me being with EDF. In general I had the opposite problem of it still not being warm enough, but I think that was more to do with the one storage heater not being enough to heat the house properly, especially in evenings when the heat has mostly dissipated. I do have info on the tariff I am on, which I think is single rate, which I’ll post below.

As a side note, I calculated from my bills over the past year and found that I was billed for approximately 2000kWh on everything else, and an additional 6000kWh on the single storage heater. I had the heater on for a couple of months, and on and off for another couple of months depending on the weather. This seems like a lot of energy to me, but it may be normal for storage heaters?

Fully agree that this community forum specifically is amazing – thanks so much for all your help!


I’ll definitely call OVO support and talk it through too. And thanks so much @Jess_OVO , that would be amazing. If I could know what the team think before calling OVO support I think that would help me a lot and would also put my mind at ease about making the switch.

I am waiting for EDF to get back to me, I’d guess they’ll reply by Friday or Monday. I’m in touch with the complex meter team there after my tariff ended and they can’t put me on the same one anymore. I found out that I am currently on ‘Flexible Control Sep21’ tariff for both meters. I think the Sep21 refers to the date I started it. It ends in a couple of weeks which is why they originally emailed me, as they can’t put me back on it. Instead, they’ve offered a similar but slightly more expensive version with a 3 year contract, which I really don’t want to commit to, as I don’t see myself living here for more than another year, especially if the energy continues to be so pricey and the heat not great in winter. The new tariffs they offered are ‘Standard variable’ for the meter that logs the storage heater and ‘Easy Online 3 Year Fix Sep24’ for the other meter. I assume that if I do not agree to go on the tariffs before September 24th, I will go onto a ‘deemed’ tariff which will be even more costly. All of these issues have led me to think it might be cheaper, or at least less annoying in the long run, or even just better for the next person who moves in here, to get a single smart meter with an appropriate tariff and be able to just forget about looking into this stuff again for a while!

Thanks for the link on storage heaters too, I will read that tonight aswell! Or tomorrow for some of these links, it’s getting late!

Userlevel 7
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No worries, you’re most welcome. I’m glad we could help in at least some way!

If you ever need a hand with your research, feel free to let us know. A few volunteers might be happy to help and I definitely would be.

As for keeping the thread unlocked, sure thing! We actually keep threads unlocked indefinitely here, even after the question has been answered - marking a Best Answer simply sets the status to Solved and highlights the chosen answer. :) We like to keep them open because it’s a lot more helpful in case anyone else needs help or wants to contribute further. Feel free to use this thread to post updates anytime. We’ll definitely be happy to hear from you!

Userlevel 2

Hi @BrightEyes161 and welcome to the OVO online community,


Firstly just wanted to say I totally emphasise with your situation - these complex meter set-ups are really tricky in terms of switching suppliers and knowing you’re getting the cheapest rates to keep your storage heaters running through those cold Scottish winters.


Our community volunteer, @Blastoise186, is all over it with the great advice. From my understanding of things it does look to be a Total Heat Total Control type setup - but I’m going to take this one away to our team of experts to check if that’s the case and if so what the options are in terms of a switch to OVO and a smart meter upgrade.


It’s definitely worth getting in touch with your landlord to check the efficiency of your storage heaters as by the sounds of it, you’re already using energy at off-peak rates to get these charged so just a change to the meter or plan might not be enough to bring the costs down. I’ve had a little scout around for some relevant advice in getting the most out of the current set-up and would really recommend giving the Centre for Sustainable Energy’s (CSE) storage heater guide a read - They’re a charity we partner with who can give some really great impartial energy saving advice.


Have EDF confirmed what type of tariff you’re currently on and why they’re not able to offer you a smart meter yet?


Hoping some of this advice is helpful - do keep us posted with any further questions. We’re always on hand here to offer advice where we can. :slight_smile:



So I don’t want to count my chickens before they hatch, but it looks like I’m getting my meters changed to a single economy 7 meter, at no cost to myself.. Not sure how this is possible given what you’ve said, but my supplier has booked it for in a few weeks. I’ll let you know how that goes and if it saves me money! I’m expecting similar or modest changes to the bill, but I think it could be beneficial given I stay up quite late and charge things overnight, etc. It also might open me up to be able to change provider, though not certain as it is a legacy economy 7 meter that works with my storage heater set up.

I’ve also been attempting to contact the estate agents about the storage heater for the past month, but they’ve yet to respond to any of my attempts.

For anyone struggling with bills in Scotland, I recommended contacting Home Energy Scotland for advice ( 

Also SCARF are extremely helpful ( They sent someone over who gave advice and brought some free draft proofing tapes and brushes, LED bulbs and some other stuff. They also offered to call my energy provider with me to help with tariffs, etc. Really recommend. 

I’m also applying for a specific health benefit that opens up grants to improve heating in homes if you’re struggling with costs/temperature and you’re on specific benefits. More information here:  I hope the estate agents might pay more attention if it’s a free upgrade.

Userlevel 7

Some really brilliant advice there, @BrightEyes161 - so good in fact, I think that deserves some ‘Best Answer’ points. 


Do keep us updated with how things go with the meter replacement. It’s good to hear you’re making progress with your current supplier and hopefully getting things sorted before the colder winter months. :slight_smile:

Userlevel 2


I got an email from EDF so wanted to update.

They offered me a “Daily Standing Charge of 27.4p per day + Unit Rate: 20.49p per kWh = est. £545.55 per year for the standard meter, and a 13.65p per kWh = est. £837.97 for the Single Heat meter. Total est. £1,383.52.”

Though they also said, on the day they sent that email, that the tariff for the standard meter is for 3 years with a £15 exit fee and is being removed today, which seems ridiculously short notice and I’ve already missed that deadline.

Interestingly, they also said that “a 5 terminal SMETS2 Economy 7 meter is what you would need because of your storage heaters, however they are not available in Scotland at this time” and “The only other meter type we can offer you is a 5 terminal legacy Economy 7 meter (not SMART at present) which would give you 7 hours of cheaper usage overnight. As you are in Scotland you may get 7 to 8.5 hours due to the weather. On your current heating meter you get between 5 and 12 hours regarding the heating dependant on the weather in your area, so going to Economy 7 you would lose a few hours of heating.” and that the price would be “Daily Standing Charge: 27.48p per day, Day Rate: 24.15p per kWh, Night Rate: 12.72p, total est. £1,406.16.”

So… going to this, at least with them, is estimated to be slightly more expensive than not changing and potentially even with less heat.. Really not sure what to do here. It might open up more avenues to change company and get better rates? But then, it being a legacy 5 terminal meter, I might still be stuck in the same place?

Maybe just staying with these meters and seeing what tariff they can give me now is best.. Though as I said earlier, the one they originally offered has apparently expired. What a mess..

Userlevel 7
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I’ve just gone in and fixed my reply to include a few extra things I initially missed.

But while you wait, here’s a couple of fun facts for you. Horstmann is known as Secure these days, I think they rebranded a few years ago but I can’t remember the exact reason for the name change.

As for English Electric… They no longer exist. There seems to be a few traces that suggests General Electric bought out the company and merged it, but they’re few and far between and it’s difficult to trace exactly what the fate of the company was.

I’ve also noticed that your meters are pretty old and are probably due for Re-certification anyway, which means they’re due to be replaced because they’re reaching the end of the service life. Certification normally lasts around 10 years, so I’m surprised yours are still going!

Userlevel 7
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I’m still researching this one at the moment, but hopefully we’ll be able to figure out your options soon.

I’ve just remembered some additional info that might be useful, so I’ll go ahead and write it down here while it’s fresh in my mind. It’s some stuff that I just remembered while browsing a few other forums and resources to dig deeper into this issue.

One of the problems you’ve got is that your Dual-MPAN setup from the two meters often creates what is known as Related MPAN’s - where there’s one for each meter but they’re both tagged as being at the same address. It doesn’t always happen, but is pretty common with complex meters. LOADS of suppliers choke when faced with these, because it confuses the systems as to which MPAN is being switched and causes the process to fail in many cases.

Here’s an example of a previous discussion that I found on here which I have been part of.

In theory, it might be possible for OVO to take on your supply, but it’s extremely likely that the self-service Quote & Switch tool via the OVO website will choke if you attempt to use it. In some cases however, it can be possible for OVO’s Support Team to manually process the switch from their end and they are sometimes able to get tricky switches to work in cases where the self-service methods break. It’s probably worth having a chat with them over the phone to discuss your situation as the team might be able to check if they can switch you without having you commit to it first. If they can, then you might be in luck but it would have to be done over the phone for the most part.

If you do manage to get OVO to take on your supply successfully, it should then be possible to arrange a Meter Exchange to upgrade you to S2 Smart Meters. Since this would result in two meters being replaced with one, you’d be converted to having just one MPAN rather than two - which also means only one Standing Charge and much easier switching in the future if you decide to move on. If this works, OVO would also be able to take care of updating the records and zapping the second MPAN for you (the second Standing Charge would be terminated once this completes).

This is all very dependent on whether OVO is able to pull this off and I can’t make any promises, but I think there’s a possible chance it might work. I have a feeling Tim and Jess might also be digging through their notes on this one, but I hope this is at least something that might help you escape this headache.

I would strongly recommend having a chat with OVO’s Support Team before making any commitments though. Please feel free to let them know about this thread as well, since the information you’ve provided here will almost certainly help them out a lot. :)

Good luck with getting this sorted! We’ll be here if you get stuck.

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Well, I have a real Brucie Bonus for you right here. And it’s pretty useful in a general context but also explains my point about certification. Feel free to check this puppy out.

I honestly don’t know how I managed to find this thing, since it’s buried so deep on GOV.UK that I don’t think many people encounter it very often. But in short, it seems to be a list of Certifications for basically every every single electric meter ever used in the UK. Except that it doesn’t seem to be fully up-to-date as brands like Aclara are missing… Still useful to have around though. Gas meters are probably in a separate document though, which I’ll probably discover eventually.

Looking through that list, I’ve identified that your Horstmann RTS Meter - which is a Horstmann NU077-122 for this purpose - and listed as a Horstmann NU077-1 in the document had a 20 year Certification lifespan… Which ever so conveniently expired almost a year ago in November 2020. I can’t find any references to your English Electric one in the document, but given that it’s got a Certification sticker of January 1996 and there seems to be very few meters that were granted a lifespan of more than 20 years… I’m going to take a wild guess and assume that it ran out in January 2016. The huge gap in the dates is definitely unusual, but it’s probably because the two meters were manufactured and/or installed at different times.

Admittedly, there are apparently a handful of meters with a lifespan of 40 or even 45 years somehow but they seem to be an exception to the usual rules. It’s an awfully long service life though…

I also randomly came across a discussion on another forum from nearly 10 years ago that seems interesting. While some of the language is a little dodgy, I’ve read through it all and I’m satisfied that it’s not too bad. Feel free to check it out if you’re interested. This definitely adds more weight to my thoughts that it’s a THTC setup. It’s also looking like your English Electric meter has clocked itself all the way back to zero at least once since it was installed. I realised this when I noticed the rotary dials on the register don’t properly line up anymore which is really common when these types of dial have gone all the way back to zero. This isn’t a sign of tampering of course - just an indication that loads of electricity has been passing through the meter over the years! Your bills shouldn’t be affected either, as most billing systems are capable of detecting this scenario and then doing some extra number crunching to account for it.

The next problem I’m seeing however, is that THTC was an SSE exclusive tariff and further research is starting to indicate that even EDF Warmwise might not be as similar as I thought it was. The problem with these legacy supplier specific tariffs is that there was almost never anything that came even close to matching them, so comparisons were impossible unless it was clear that it was just a cosmetic thing for marketing and branding purposes (which was really rare). I can’t see how you’d be able to get EDF to do any kind of off-peak or Economy 7 type tariffs with this complex meter setup, because that Horstmann RTS Meter is almost certainly going to blindly react to the same control signals as all the other SSE THTC meters with the same Group Code - it won’t have a clue that you’ve moved to EDF and that THTC no longer applies to your supply.

SSE’s Total Heat Total Control tariff (aka Total Heating with Total Control to give it the full name) also responds based on the weather forecast for the area as well. According to SSE, the off-peak hours can run between five and 12 hours per day based on the weather forecast and SSE would switch storage heaters and water heaters on and off via the control signals based on what they believe is appropriate for that day. If the weather forecast is looking pretty sunny and warm, then it’d be more likely that your off-peak hours would be closer to five hours, but if it looks like it’s going to be a snow storm with freezing temperatures, you’re more likely to get closer to 12 hours of off-peak.

There’s also certain things that get the cheaper rate 24/7 like electric showers and towel rails. So that makes things even more complicated - especially the wiring! This would have been a possible option back in the day, but sadly it no longer exists for new customers.

On the other hand, EDF Warmwise appears to be a legacy tariff that merely grants eight hours of cheaper electricity per day, but according to the MSE Forum, there’s references to having a single meter with four rates. This appears to be backed up slightly by the only reference to Warmwise that I can find on the EDF websites. That page is literally the only one that still exists for some reason. In reflection, I now start to feel that you’re probably not on Warmwise at all, since it doesn’t seem to match up to your meter setup at all.

At this point, I feel as if I can start to understand another possible reason why your bills are so high. I get the impression you’re on a single-rate tariff in a scenario where Economy 7 would be a lot more appropriate. Although it is possible to use this complex meter setup on a single-rate tariff (the supplier can just take all the readings and run the numbers to get a combined total), I can’t really see how you can get anything like Economy 7 with this arrangement. If the RTS Meter is reacting to THTC control signals rather than E7 control signals then it basically makes E7 style billing impossible to calculate. There’s not really any way to reconfigure the Radio Teleswitch either, short of replacing it with another one - and in your case that would mean replacing the entire RTS Meter, since the Radio Teleswitch is built-in on that particular model. And if you’re going to have that done, you might as well just upgrade to Smart Meters anyway because chances are that EDF no longer offers complex tariffs like Warmwise or Heatwise. And the fact that the RTS Service is slowly being decommissioned means that it would be unwise to install RTS Meters now, outside of replacing faulty meters on a temporary basis.

Jess is still waiting to hear back from the team and it might take a while, but I hope you’re OK with that. We’ll definitely keep you posted if we manage to get any updates or figure out anything else.

Oh, and I think this serves as yet more proof that community forums are an absolutely amazing resource! You would never get this kind of discussion going on most social media platforms, that’s for sure!

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I completely agree with you with pretty much everything. But sadly, these legacy metering setups cause so many nightmares that even with the current rules it’s really difficult to migrate off of them and get onto something more appropriate.

I like your thinking about having the landlord replace the meters, but I’m afraid that’s not an option for legal reasons. The meters are owned by the supplier and they’re the only entity who is permitted to break the tamper seals and work on the meters without needing special dispensation from the supplier. Your landlord would get in a lot of trouble if they attempted a MEX themselves.

Definitely worth talking to them however if you’re concerned about legal issues with your tenancy. I can’t really dig into that sort of thing here as I’m not qualified, but Citizens Advice probably can help you out.

There is only one incentive for EDF to replace these meters that I can think of. And it’s to do with the RTS Service. While the plan is to support RTS Meters and keep the RTS Service going until everyone has moved off of it and the user count hits zero… The equipment used at the transmission sites is getting pretty old and definitely won’t last forever. I just hope EDF considers that factor and makes an effort to keep your supply running properly. Because if the RTS Service suddenly goes kaput and can’t be fixed… I just can’t bear to think about the consequences. My understanding is that there’s at least another couple of years left in the valves on the transmitters though, so it’s not quite as desperate as things might seem. But they will blow eventually, even with the highest possible standards of maintenance.

But regardless of that, you’ll almost definitely want to avoid the trap of Standard Variable tariffs, since that kind of tariff will basically destroy your bank balance. If you’re able to get the Warm Home Discount, that might at least knock a little bit off your energy bill - and a £140 discount is after all, better than no discount.

That’s all I can think of at the moment, but I’ll let you know if I discover anything else.

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No worries. :)

In your case, that would be EDF as they’re the current supplier. Ownership of electric and gas meters gets a bit weird when you’re no longer on-supply with the original installing supplier like SSE, but I generally refer to the current “owner” as being whoever you’re currently with as that makes it a little bit easier to work with.

You can apply for EDF’s Warm Home Discount right here once it opens. Don’t worry about them getting any free SEO out of this - cuz they won’t. :stuck_out_tongue:

I know the forum extremely well and while my Super User role allows me to bypass almost all of the usual anti-abuse mechanisms, I’m still subject to the one that causes Google to not follow that link. Muhahahahahaha!

Userlevel 7


So I’m at the stage now where I think you’ve given me all you can for now - thanks so much again. Hoping this thread is useful to someone else down the line.


Our pleasure, @BrightEyes161 - and thank you to yourself for asking the important questions - no doubt there’ll be others in a similar position who will benefit from the information accessible here - it’s what this place is all about - sharing knowledge and information to help others with their energy related queries.


If it is useful, you can keep this thread unlocked and I can provide updates with what they say?


As @Blastoise186 has already highlighted, threads always remain unlocked here - even if you decide to select a ‘Best Answer’. We’d really love to hear the advice you get from others - keep us posted. :blush:


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Hey, welcome back @BrightEyes161 !

That’s great news, glad to hear you finally got things taken care of. :)

Hopefully this should result in your bills dropping slightly, as I suspect the second MPAN will be terminated, along with the related Standing Charges. Paying only one of those will always be cheaper than paying for two. This will also make it a little bit easier to switch supplier in the future, should you wish to do so.

Please allow up to three months for the redundant MPAN to be fully terminated from your property and be reflected in both the bills and your account. ECOES will of course be updated with the new meter details and MPAN data as well, but it just takes a while. Either way, the Standing Charges for the removed meter/MPAN should cease as of the date that meter was removed, even if it doesn’t show up immediately.

As for getting gas… At this late stage I personally wouldn’t recommend it unless there’s already a gas main in your street. Gas is being slowly phased out over time in the UK, and the amount of time, effort and resources required to get a gas supply set up now - especially if there’s no gas mains nearby - is potentially unviable unless you seriously need it badly. The UK is moving more towards electric only and as gas prices creep up, the price advantages of gas are being slowly eroded. This isn’t to say it’s definitely out of the question, but may be worth factoring into any decisions.

Mind you, a couple of months ago now, someone from a housing association in Scotland actually reached out to me via PM to ask about similar matters after seeing one of my guides. I did respond to them, but I never heard back… I’ve decided not to reveal their identity for privacy reasons, and out of respect for the fact it was via PM.

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I’m afraid I can’t make much use of your MPAN’s unfortunately. As a forum volunteer, I don’t have access to ECOES and Xoserve, so I can’t look up electric meters and MPANs on ECOES or gas meters and MPRNs on Xoserve. However, all energy suppliers do have access and they’ll be able to do a lookup for you.

I think any supplier can do a lookup, but only your active supplier can make changes. You are allowed to request a copy of your records free of charge. What you do with that data is of course up to you. :)

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No worries, you’re most welcome. Figuring out extremely tricky puzzles is something we absolutely love doing here - and ultimately I want you to be able to leave here with the best possible advice that not only acts in your best interests, but also your landlord as well. I think your landlord and the rental agency would be very keen to read through this discussion - and no doubt they’d be more than happy to do away with the current metering setup!

While the OVO Forum is primarily volunteer led, Tim and Jess are also on hand to help with moderation tasks and also to provide extra help with some of the more complicated questions. And in cases like yours, they’re able to ask OVO’s internal teams for even more advice. The mysterious Smart Meter Friend is seriously good with these complex meters as they know a ton about them - so they’re not just a Smart Meter expert! But even I don’t know the identity of the mysterious expert because Tim and Jess won’t reveal their identity even to me! XD

You basically have unlimited access to the forum whenever you need help and we can help with almost anything that isn’t account specific… Or paying the bills… We tried to build a TARDIS for that, but it kinda disappeared into the Time Vortex and we’ve never seen it since.

Anyway… Let’s get back to the action!

It’s really difficult to switch suppliers/tariffs with complex meters. Not only will suppliers often outright reject the switch, the few that can handle them often struggle later on - or end up giving you an even worse deal than before. You also can’t use price comparison tools of any kind… Because basically none of them are capable of recognising complex meters unless they’re Economy 7/10/White Meter.

Your current meter setup was almost certainly installed purely with THTC in mind. Jess is asking OVO’s Smart Meter Friend for an expert opinion, but I’m highly confident that I’ve managed to identify it as being one. Every single resource I’ve got points at your setup being intended for SSE THTC and in actual fact, if you were to ask OVO or EDF (or basically any supplier) to do an ECOES Lookup for your address, you could probably retrieve a full Supplier History and Meter History pretty easily. I bet you a Mars Bar that SSE would be on there somewhere. I honestly have no idea how on earth someone managed to hack/bodge a switch to EDF though, because it seems extremely clear to me that EDF cannot support your meters properly. Unless a previous tenant managed to pull off some kind of black magic or used a voodoo doll somehow… I just don’t know how that happened. But in short… Yes… You appear to have SSE THTC meters that have been dragged kicking and screaming over to EDF, despite EDF not supporting them and since the meters don’t know you’re with EDF now, they’re still listening for SSE control signals and reacting based on what SSE THTC thinks your meters should be doing. EDF has no say over this behaviour… And unfortunately you don’t either. So yeah, the weather dependent control signals probably are causing your flat to be a desert at weird times, while turning you into an ice cube when you really need to keep warm. Because as we all know, the weatherman always gets it wrong! :stuck_out_tongue:

But it gets even worse for you - and yes, those usage figures are extremely high and are definitely a factor in your high bills. You’ll definitely want to chat with your landlord about your options to upgrade the heating to something less power hungry.

The problem you have is that while SMETS Commands for Smart Meters always target individual meters on a one-at-a-time basis (everything else gets ignored), RTS Meters will just blindly accept basically anything that seems like a valid control signal for their group, even if it’s not actually meant to target a particular meter due to a tariff change. In your case, while you’re no longer on SSE THTC, your Horstmann RTS Meter is still responding to SSE THTC related control signals and it’s impossible to force that meter to listen for Economy 7 control signals instead... Unless you to break the anti-tamper seals and get zapped with 240 volts of eco juice from the nearest wind farm (don’t do that!).

Either way, a THTC Meter will always be a THTC Meter for its entire service life and it will never know whether or not you’re still on THTC. That’s one of the downsides of the Radio Teleswitching Service - it’s a one-way system and it’s completely impossible to target a single meter, so good luck using RTS to reprogram one and disable THTC functionality (because you can’t).

To me, I feel as if EDF are ripping you off a bit with even more confusing tariffs. If you do nothing, you’ll be automatically dumped on their Standard Variable tariff once your fixed term deal ends - and it’s likely to end up costing you even more than it does now. But at the same time, it’s a gamble to enter into a new contract with EDF if you’re planning to switch to OVO or any other supplier, as you might get punished with Exit Fees if you do. So if you’re planning to leave, I’d suggest going onto their Standard Variable tariff for the short time remaining until you switch away. I would strongly recommend against locking yourself into a three year contract with your current arrangements, even if you aren’t planning to move out it’s just too risky. If you stay with EDF, it’s likely a case of having to pick the best from a bunch of bad options - and the best is waiting for them to eventually get you a Smart Meter upgrade.

To get a better idea, I just went on their site and threw in a random postcode into their quote tool and it threw 10 different tariffs at me. Admittedly, I did lie to it by putting in completely fake details, but even then 10+ tariffs from one supplier is excessive. I gave up after I noticed that their website was trying to spy on me using SessionCam (I HATE overly privacy invasive analytics like that) so it’s a good thing I have my UDM set to block that junk. To make things worse, Octopus presented me with 60+ tariffs when I punched in the same details into their website. Too much choice!!!

The Sep24 reference is basically the month and year that the tariff will end if you were to sign up right now, unless otherwise specified. And this just makes it even more complicated than it needs to be. Because I’m pretty sure there’ll soon be yet another version of the same tariff with a new name and rates.

I never really see any valid reason why there needs to be so many tariffs. OVO only has a handful which mainly consists of a Standard Variable, One Year Fix, Two Year Fix and a Smart Meter Special. The names always stay the same, while the rates quoted are based on what’s available to you at the point you generate them. That’s realistically all it needs to be and makes my life so much easier. Especially because I also rent my flat.

But luckily for me, I’m on a simple bog standard Single-Rate setup with my S2 Aclara SGM1411-B called Raichu doing a brilliant job of getting my readings sent to OVO reliably, and two Chameleon IHD6-CAD-PPMID IHDs that I call the Kecleon Brothers doing a pretty decent job of letting me track my usage whenever I get them close enough to Raichu to pick up the signal (fire rated walls do not help with that!).

But yeah, I’m seriously glad you stopped by to ask for help because this not only gives us even more useful forum content for other visitors (we get over 60k hits a month on here!), but it also means you’ll have a much better idea of what you can do without the risk of gambling in the dark. Even if that means you don’t switch to OVO, I’d be much more comfortable with you getting the advice that helps you out anyway and I obviously don’t get any reward out of helping out here… Other than racking up loads of points on the forum leaderboard (which is more just for fun than anything else).

Personally, I’d feel pretty bad if I was in your situation and moved out to force a new tenant to have to deal with the mess - especially if they don’t know anything about this stuff and have no idea what to do. The actions you take to upgrade the meters and heating/hot water now will have an impact on your landlord and future tenants. I absolutely applaud you for doing the right thing and I think it’ll pay off in the long run.

Userlevel 7


Fully agree that this community forum specifically is amazing – thanks so much for all your help!


I’ll definitely call OVO support and talk it through too. And thanks so much @Jess_OVO , that would be amazing. If I could know what the team think before calling OVO support I think that would help me a lot and would also put my mind at ease about making the switch.


So nice to get such kind feedback on our little community and the work we’re doing here, I’m really hoping our advice will help you and others in a similar position who might stumble across this thread in future.


I’ve heard back from our metering expert on this one and it’s a really tricky situation. Depending on where you live there are certain areas of Scotland where the replacement of these type of set-ups with a smart meter is being complicated by limitations imposed by the DNO - meaning even if you were able to switch supplier you currently wouldn’t be able to get the meter replaced for a more straight-forward dual-rate smart meter. This is something that all suppliers are working really hard on, in conjunction with Ofgem, to find a resolution. It’s worth mentioning here that there’s no guarantee that an Economy 7 would be more cost-effective, as depending on how your storage heaters are set-up often a ‘Total Heat Total Control’ -type  plan offers more off-peak hours than an Economy 7 setup.


I’m really sorry that this might not be the answer you’re looking for, and to clarify OVO’s position - as we don’t have a tariff to support your meters we’d be unable to offer you a switch at the moment. However our team has confirmed that this type of plan is not exclusive to SSE and EDF is known to have plans which are compatible to this setup.



I am waiting for EDF to get back to me, I’d guess they’ll reply by Friday or Monday. I’m in touch with the complex meter team there after my tariff ended and they can’t put me on the same one anymore.


As with SSE, suppliers who have customers with a radio-tele-switch meter set-up have a duty of care to ensure that you are supported until the point a meter replacement is possible. We’d be really interested to hear what advice they are able to give on this one and the decision you decide to make. Worth mentioning here that if you do decide to move out before the end of you plan, no exit fees can be applied so there’s no danger in fixing in to a longer plan and closing your account were you to move before the plan ends.


Let us know if this offers any helpful insight - I’d also really recommend working with your landlord on this one. Whilst a meter exchange or switch of supplier might be a challenge at the moment, having an electrician check the efficiency of your storage heaters and that they are wired correctly to your current meter setup, could make a real difference to your energy usage/costs this coming winter. 


Userlevel 2

Hi all. Thanks for all the info again, very helpful!

Thanks so much for looking into that @Jess_OVO, regardless of the outcome! I believe my DNO is SSE, from what I checked on a couple of websites. Can I ask what the complicating limitations are? I’ve read a bunch of the links you have both posted and somewhat understand some things.. but if possible, it would be useful to have a condensed version of what is happening here that is preventing someone like me from getting my meter system updated and thus being able to choose a better tariff, especially since, as mentioned earlier in the thread, at least one of my meters is past it’s certification lifespan and these meters are due to be phased out any time now. Should this meter be changed now legally? Whose responsibility is it to change these meters? And a related question, why can’t OVO bring me over and change them?

I know you said that you don’t recommend going on one of their tariffs @Blastoise186, but one option I’m considering is staying with EDF, going on the 3 year tariff they suggested and just paying the £15 exit fee when I move out. Though, @Jess_OVO, you said they can’t charge me an exit fee? They did say in the email I received there is this exit fee. Could you give me any sources I can show them that confirm this? Even if they did charge me an exit fee though, it would probably cost less if I stayed for around another year than if I didn’t go on a tariff at all. I’m at least going to wait and see what they reply about tariffs and smart meters. I’ll update here about that as I go along. This tariff option will be more expensive than last winter, so I’m obviously not happy about it, but if that’s all I can do regarding the tariff that’s how it’ll be I guess.

I’m talking about ‘one option’ here like I have any other.. It’s quite frustrating that I appear to be locked into whatever EDF offer me. From what you’re saying, I can’t shop around, I’m stuck with these meters and this tariff until EDF choose to do something. So.. where is the incentive for EDF to actually do anything there? I’m not arguing that they are unscrupulous as I have no idea, but if they or another company were to be of that ilk, they wouldn’t prioritise installing smart meters, as that enables customers to leave, and therefore they could lock customers into this high-cost system indefinitely. That’s a really naff situation for someone like me to be in and surely breaks some legislation somewhere..? I was under the impression that everyone should be able to change provider without constraints. And who decides what a duty of care for them even looks like until they fit a new meter and a better tariff? How do I even aim my frustration somewhere practically useful here?

I’ll definitely start putting more of my energy into looking into modern storage heater solutions, if there are any grants for that, and asking if the landlord will fund one, or at least getting my current one checked, thanks! I read on a tenant information website that ‘The minimum heating standard is at least 18°C in sleeping rooms, and 21°C in living rooms, when the temperature outside is minus 1°C and it should be available at all times.’ The website cited the Landlord and Tenant Act (1985) but I did not find any specifics around temperature on it unfortunately. I just worry that my landlord will not agree and I will be stuck in an even worse position than last winter in terms of temperature and cost.

Edit: is it possible for the landlord to change the meters privately? How much would that likely cost?