If it’s a Load Managed Area and you’re keeping the storage heaters, then yes. THTC must remain in place regardless of meter type. If it’s NOT a Load Managed Area and/or you’re happy to dump the storage heaters, moving to regular Economy 7 (well, White Meter since you’re in Scotland) is potentially an option.
Just about any Smart Meter can handle basic Economy 7 functionality i.e. flipping between Peak and Off-Peak registers. However only certain models can handle full functionality, such as the SMETS2 Aclara SGM1416-B. That one has built-in functionality to flip circuits on and off as part of E7 schedules and there’s actually loads of them in OVO’s inventory. It’s other suppliers who rely too much on the Landis+Gyr E470 that are struggling, because L+G doesn’t make Five Terminal Smart Meters.
It kinda helps by the fact that OVO installs the Aclara SGM1412-B, SGM1415-B and SGM1416-B only for members who actually need one. It helps to conserve the stocks and reduce wastage.
There is little to no provision for installing non-smart Economy 7 meters anymore. A couple of years ago, OVO was installing a few of those in VERY low volumes for specific edge cases, but don’t count on it being an option now. The default position remains of installing Smart Meters and if that option is possible, you can’t get a traditional meter.
However, there is one person who knows some stuff that I don’t. Please bear in mind that he might not respond today due to current events, but I will let @Lukepeniket_OVO know about this thread in case he knows anything.
It may also be worth mentioning that Aberdeen might be one of those Load Managed Areas, but I can’t say for sure. I know we’ve encountered them before on the forum and the last user was somewhere in the north of Scotland...
After a morning of phone calls not much has changed.
SSEN, the DNO, were pretty useless. Although I’d put that down to the idiot that answered my call. Right now it doesn’t really matter if I’m in an LMA though.
SSE’s complex heating team couldn’t do anything except give me a bit of an explanation of how THTC works. I SHOULD have 24/7 cheap hot water, panel heaters and electric showers. Although it seems like someone who doesn’t fully understand THTC has been fiddling about, if you look closely at the consumer unit for heating you see “shower” has been scribbled out and a new “shower” switch has been installed on the “normal” circuit consumer box.
I’ve had to sign up with octopus for now. Absolutely brilliant company with friendly staff, no more Indian call centres! The treat the grey meter like a semi-functioning economy 7 it seems, where only the off-peak rate is recorded. Their prices are better than what I’m currently paying with SSE in my old property!
Also phoned Scarf, a charity which helps people with energy in NE Scotland. An advisor of theirs is coming out soon to try and help me with understanding the heaters and meters, changing suppliers etc.
I think the plan right now is to wait for Scarf to come out, then probably switch to SSE, see what can be done about the meters as they’ll need changing soon anyway and maybe go back to octopus.
When all is said and done, the THTC system is a bit like economy 10 but without the downside of higher peak charges. Well, that’s how I see it right now anyway.
I may have just gotten some results for you. Since I don’t have your MPAN, I can’t say whether an LMA is relevant to your specific supply (and I’m not allowed to know your MPAN anyway!). However, I just spoke to someone else at the SSEN New Connections Team and they told me that you can find out this information if you send an email to ge@ssen.co.uk with both of your MPANs and ask them to check whether it’s in any LMA.
They’ll respond within five working days. The response will include information from the teams who deal with this stuff, so it should have what you’re after.
I’m pretty friendly with lots of DNOs so I can sometimes get information out of them which can be tricky to get otherwise.
Thanks @Blastoise186, they must keep that email address buried deep within their website, I certainly couldn’t find it!
That’s because they don’t want you to find it that easily. I just told a few of their call centre advisors that I’m a forum volunteer here and boom! Instant answers. I don’t really know why it works so well either… It just does for some reason.
Oh yeah, I just realised we never answered part of your question!
The answer to Does Scotland get 8.5 hours of Economy 7 is Yes. Technically, it may be called White Meter up there but it’s close enough (what’s in a name comes to mind!). Your hours for the South of Scotland is 8.5 but it’s the standard 7 in North of Scotland. For the former, the times are 11:00PM to 7:30AM, for the latter it’s Midnight to 7AM
We’ve got that covered at
and also the DNO list at
Thank you @Tim_OVO and @Blastoise186,
So the south gets more off-peak time than the north? That makes absolutely no sense! Then again, the past week has taught me that very little regarding electric supply is supposed to make sense to mere mortals like myself...
So what’s been happening recently?
Well, nothing much really…
I had the scarf advisor round today, apart from some advice about loft insulation and talking to octopus to get the meters changed I’m too energy efficient for him!
Its about £4.40 to have the living room storage heater do an overnight charge for 7AM-8PM of heat at 21C. Going up to about £5.17 tomorrow.
There’s no point going to SSE about changing the meters as I’ve been told they have a rigid schedule which they will stick to for changing people over. So I’ll be sticking with octopus for a long time I think. Their great customer service is a real selling point! (Take note SSE, nobody likes talking to somebody in India about their energy usage in the UK...)
I’ll have to do some calculations about getting octopus to switch the meteres over, the scarf advisor suggested E7 or E10, but seeing as I use most of my energy during the day, I’ll be seeing if its worth switching to a single rate smart meter.
I might just be worth going to the single rate as having a second electric meter will cost £186 ALONE in the standing charge, I barely use the heating so I’ll have to see.
@Blastoise186, Re; LMAs. SSEN were absolutely useless, I either get sent in a circle of people to contact, told that I can have my load increased or to talk to my supplier! Looks like it’ll be yet another ‘Octopus saves the day’ scenario...
Ongoing nightmare of extortionate bills in a relative’s rented studio flat with ancient electric storage heaters and a 2 meter system. One rate is Standard Evergreen, the other THTC (Total Heating Total Control). Supplier is SSE/OVO. Property is in North East Scotland.
The THTC rate is supposedly a cheaper rate for off peak energy delivered to hot water heater and radiators overnight but I debate whether the radio control switch is still being provided for this. Bills are averaging £300 a month (paid quarterly from meter readings, not estimates) which is ridiculous given the size of the flat. He his afraid to have storage heaters on now and uses a plug in panel heater with thermostat in one room only most of the time.
I arranged to have a timer switch on the boost element on the water tank and switched off the main element to try and save some energy. Thus, the top of the tank is heated for a couple of hours a day to allow for a shower/washing up. Washing machine, oven, hob, tumble drier are not used due to disability. My relative has been forced to have 2 of the old storage heaters on during the very cold spell we’ve had recently but these heaters have no control panels or thermostat - they are either on or off. The largest of the storage heaters has input/output controls but it remains switched off at the wall as the dials have melted (oh the joys of private renting).
My question is, could we have the old storage heaters disconnected and have the THTC meter removed, leaving one meter/one rate? What would this involve? We just can’t fathom where the energy is going and I can’t help but be suspicious of the 2 meter/rate setup.
Thanks for reading this far! Any advice appreciated.
Sounds terrible @THTCnightmare
I used to have huge electricity bills as my hot water was only heated with an immersion and I had no way of knowing how hot the water was. As it’s probably the heaviest use of electricity in the flat I’d try reducing the time it’s on even further. It’ll be like having the kettle on for two hours solid. If it’s as ancient as it sounds the thermostat probably isn’t switching it off once it comes to temp.
It may be worth reading through some or all of this thread:
Hey @THTCnightmare,
That sounds like a really complex and frustrating situation to be in.
I’d advise contacting your previous supplier, they may be able to book in a Site Survey for an engineer to come and asses the situation first.
We do have some topics on THTC which may have some helpful information- @juliamc has already shared one:
I have just moved into a property in N of Scotland on THTC with SSE/OVO.
Find it all v confusing and v expensive. Heating is from radiators with outdoor air source heat pump. No storage heaters here which seems to be what THTC is set up for? Costing a fortune! 2 working adults so out all day, using woodburner in the evenings but got a bill for £662 for our first 6 weeks here! And no, not an estimated one. Seem we are on a super expensive traffic and can't switch from it. When I phoned I was told they dont deal with "exotic" meters. What to do?
Can you tell us more about your heat pump ? The best way to run it is to keep it running 24/7 which seems counterintuitive if you’re out all day. You just need to balance the heat loss of the building. Is it set up with weather compensation ?
In truth I dont a lot about this air source heat pump beyond that it pulls cold air in, then uses electric (on the higher of the 2 tarriffs) to convert to heat. It is on 24hrs, but I've lowered the temperature control thermostat to 17.5 daytime and 10 degrees overnight so it doesn't trigger the heating. We've been relying on the wood burner for heat.
I called Ovo again and spoke to someone in the "exotic" meters team. My understanding was that the dual meters needed replaced to a single one so I could switch tariff. But he said that are not in a position to change the meters, and that if I supply a read he would convert me to a single tarrif. I was somewhat sceptical of this, worried it would end up costing even more. He reassured me it "should" be less expensive but couldn't on the phone call supply actual costs to me. And that was after 37 minutes on hold to speak to someone.
Is there anyone else out there on these THTC meters, particularly anyone with radiators rather than the storage heaters this was designed for?
Realistically speaking, THTC is only suitable for Storage Heaters or possibly Immersion Heaters. It’s a terrible option for basically anything else
And I have neither storage heaters nor immersion heater. I think there were storage heaters at some point but the previous owner changed to radiators.
We moved in mid January and have been paying huge amounts for very little.
Can any one advise on our best option?
I’d do what OVO suggests if possible. It’ll almost certainly be cheaper. Heat pumps don’t “store” anything as such, so tariffs like THTC are terrible for them
Hi @Rosey What make is you heat pump ? can you post a photo of it. There’s a good few people on here who can help you get more out of it than huge bills !
You could find that you can heat the house during the cheap times available on your tariff, then turn it down during the expensive times, so the fabric of your house acts as the storage device. Whoever installed it probably should have left you some info on how they were running it.
That’s the problem. THTC doesn’t have fixed times for the cheaper rate. It can be random and is controlled by the supplier via RTS.
Once the RTS Service eventually shuts down, all THTC meters will just run off of defaults and/or last known configs and the times will always be consistent, just like having a static timeswitch.
It’s impossible to predict when they’ll be. Taken from SSE:
What are the times for THTC?
The specific times for the off-peak rate depends on the weather forecast for your area, but you'll get between 5 and 12 hours each day. THTC works by storing up heat in your storage heaters and hot water tank during the off-peak times.
Other electric heaters and heated appliances can also be used on the cheaper rate. The off-peak rate is available 24 hours a day for panel heaters, focal point fires, bathroom heaters, towel rails, the hot water boost and even electric showers. You'll need to get an electrician to make sure all those appliances are connected to your cheaper-rate meter if you're not sure.
Ah, gotcha 
♀️ I’ve clicked ‘like’ but I can’t say I do like it !!!
So if the heat pump is wired into the off peak supply is that more expensive than the storage heater supply ? Ie three tiers ?
THTC is weird. I’m not even sure if you’d be allowed to wire a heat pump into either of the cheaper rates. I get the feeling it’d have to be the expensive one.
It’s definitely worth setting the heat pump up to tick along quietly in the background the @Rosey i assume it’s doing your hot water ? Can you let us know what time it’s operating and the temp settings etc. ??
Having read back through this thread and found the link to Scarf: https://www.scarf.org.uk/householder/hes/home-renewables/ I wonder if anyone there can suggest the correct way to set up your heat pump to make best use of the thtc supply ??
It’s impossible to predict when they’ll be. Taken from SSE:
What are the times for THTC?
The specific times for the off-peak rate depends on the weather forecast for your area, but you'll get between 5 and 12 hours each day. THTC works by storing up heat in your storage heaters and hot water tank during the off-peak times.
That’s the one thing I really don’t understand, even though SSE keep saying it. To me, THTC is predictable!
Heating charging from 1:40 AM - 7:40 AM and 1:40 PM - 4:40 PM.
Although that may just be me as I haven’t felt the need to switch from octopus to SSE in the 6 months since I posted this thread. Octopus bill the heating meter as a 24/7 off peak economy 7 meter.
Out of interest, does anyone know if SSE/Ovo has a list of all properties with exotic meters and would have a responsibility to inform such residents that their meters will need switching?
