My new home has a Total Heating Total Control (THTC) system. How do they work?

It gets worse. While this is theoretically unlikely to happen, if the RTS Signal fails while you still have the current setup, your THTC Meter will be jammed in whatever state it was in after the last successful control signal was received before the failure.

This will either mean your storage heaters are left jammed on and you get a really hot house, or your house turns into an ice cube when the storage heaters fail to activate.

There is currently only one known model of Smart Meter that is capable of handling a THTC setup. Ironically, it’s from the same company that manufactured your THTC Meter, Secure. To make things worse, it’s a SMETS1 too...

I can’t get to their website right now though as the TLS Certificate for it has been revoked and erm… Well…

Yeah…

If I try to get Bitdefender to step out of the way temporarily, Chrome will only block me anyway for the same reason. But then again, it was issued by GoDaddy so I’m not surprised because GoDaddy is just terrible! XD

There is no-one currently known to be using a THTC capable Smart Meter that we’re aware of.

Thanks @Blastoise186, looks like its a wait and see situation. How long those of us with RTS meters can wait for seems to be a guessing game...

No worries.

I wouldn’t recommend trying to talk to Octopus about any of this, purely because there’s a very low chance they’ll actually have anyone who knows about this stuff and I can’t reasonably foresee them having anything equivalent to SSE’s complex heating team. I’m supplied by OVO these days, but I used to be an SSE customer until just after OVO took over. You could say I basically jumped the queue and switched pretty quickly, since I knew it was going to happen eventually anyway! Pure luck has occurred in the two years since which has put me in a rather… Fortunate position.

I’ve only got a bog standard Single-Phase Single-Rate supply myself, nothing fancy other than having a SMETS2 Smart Meter installed by OVO after they managed to (accidentally!) brick the SMETS1 meter that SSE originally installed.

As it also happens, the only suppliers that seem to have complex heating teams who can give the advice you’re after, are those that were known to support THTC which basically means (from memory!):

• SSE
• EDF
• Scottish Power

I don’t know of any other supplier that offered it. Either because they’re gone or because they got took over and the buyer didn’t support THTC at all. Technically, OVO is too young to have had THTC support, but the takeover of SSE’s retail division has changed the game.

The ultimate answer about the wait is… How long is a piece of string? I can definitely say there are plans to migrate properties like yours, but it’s a complicated process!

Thank you so much @Blastoise186, I’ll try and keep you somewhat in the loop and can hopefully end up providing the solution to anyone else struggling with THTC in the future.

Does the new system have to be equivalent to the old?  I don’t see that as being possible. Surely the only sensible solution is economy 7 and Octopus should be able to handle that - If they can get their hands on an economy 7 smart meter.  Other forums suggest there is a supply problem at present.

its a possibility that a charge for changing the meters might be proposed, but if the meters are out of certification, then that might not be an issue.  There must be lots of customers with this sort of issue, I doubt that you’ll be the first they’ve dealt with.

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!