Dual tariff economy 7

QrizB

I still can't see any need for a meter change.

You have E7 now, and you will still want E7 with your new Dimplex Quantum storage heaters.

It's all very odd.

matt_drummer

QrizB said:

I still can't see any need for a meter change.

You have E7 now, and you will still want E7 with your new Dimplex Quantum storage heaters.

It's all very odd.

Isn't it because the old heaters work on a separately fed circuit that is only live during E7 hours whereas the new heaters have the ability to be live at all times but would require two live feeds?

That would require wiring changes.

With one live feed to the new heaters the E7 usage would be controlled by the heaters internal programming rather than the meter but they would then be able to be used outside the E7 hours?

The installer appears to be suggesting that would require a meter change.

Gerry1

Ideally the Quantums need both a 24h circuit and a cheap rate circuit switched by the meter.  However, they can be wired and programmed to operate from only one 24h supply.

If there's only one circuit it's critically important to get the programming correct.  This means understanding and doing it yourself, not relying on default settings or the installer (who won't be there around midnight or dawn to check the times).  The big risk is that the meter's actual E7 times vary from what you may have been told.

You need to observe the times when the meter on the wall switches over and back (and beware a possible 2hr peak rate interlude in the early hours).

Better still, arrange for one of the switched outlets to have a neon indicator so you can see at a glance when it's cheap rate e.g. after GMT/BST changes.

Also beware of the convector element kicking in automatically at expensive daytime rates if it gets chilly in the afternoon or evening.  You can programme it not to do this.

matt_drummer

Gerry1 said:

Also beware of the convector element kicking in automatically at expensive daytime rates if it gets chilly in the afternoon or evening.  You can programme it not to do this.

Or not if you value comfort over money

Maybe the OP wants the ability to have extra heat available outside of the E7 hours when the stored heat has gone, it seems to be part of their plan?


Sound advice though, as usual. 

RedFraggle

I have quantums and they are that good at holding heat I can have 21C from 8am to 10pm but yes, they need a 24 hour supply because of the constant temperature monitoring and running the "intelligent" side of things. 
Fantastic heaters. Worth the outlay. 

Scot_39

Depends on the locations etc. and the state of the existing consumer units and wiring etc - if its that old they may need work anyway.

But from other posts here of those who have upgraded - sure they have said nothing about work done in the meter cabinet or consumer units to do so.

For a minimal cost if in situ replacements with a like for like rated new heater - potentially the simplest solution - assuming the existing are fed from the switched E7 hours only supply - then that should be wired to the new heaters main charge input.

And sure others posting here have had the daytime live 24/7 feed to their new heaters - simply taken as spurs tapped off from the normal 13A socket ring main.

AFAIK the requirement for direct from consumer unit dedicated spur only applies to the main charge input.

As posts above the Quantums are one of the few that can be wired either dual or single wired - see page 8 of

https://product-portal.gdhv.com/sites/default/files/2023-08/Quantum G10 Installation User Instructions - Issue 5.pdf

As above the main issue in operation is keeping on top of the charge window timing - vs the meter (and old analogue meters and RTS meters - can vary over time - and not just with GMT / BST).

The worst thing you can do cost wise - is use a lot of heating on daytime peak rate.

So if got it wrong by an hour - that could in my case - 1 large - 2 medium - pull nearly 7kWh - and that at c35-40p rather than 15-20p on many suppliers E7 splits.

And of course at install time - as that would also be the main charge input - it does have to come from dedicated spurs (point to point wiring with no user plug/socket ) all the way back to consumer units.  And that will only work if the whoe house is metered at E7 rates off peak (many older legacy - e.g. dual meter RTS / E7 systems do not work that way)

Try searching and reading other threads here - on storage heaters.

Most favour the dual cable route - to avoid risk of peak rate charging - and it would be essential for other brands - and cheaper units like the Creda TSRE range (now part of Dimplex)  (which might be worth a look if dont need all the bells and whistles of the Quantum RFs - they are not strictly HHR NSH - but likely to be a major step on very old ones and a £2-300 cheaper at some sites at top end)

lohr500

QrizB said:

I still can't see any need for a meter change.

You have E7 now, and you will still want E7 with your new Dimplex Quantum storage heaters.

It's all very odd.

I agree with QrizB.

If there is Economy 7 in the property now AND the storage heaters are supplied from a dedicated Economy 7 consumer unit (Fuse box) then there should be no need for a smart meter.

Yes, ideally the Quantums should have separate permanent live and Economy 7 feeds to avoid relying on the internal Quantum timers, but surely the required wiring changes to achieve this would be needed regardless of replacing the meter or not.

I still don't see how changing the meter will save £2000 on the install.

If a dual feed to the storage heaters is needed, then wouldn't the electrician convert the existing storage heating wiring to become permanently live for the high current supply? Utilising either the existing Economy 7 consumer unit but now connected to the 24/7 live side of the meter, or by moving the storage heater high current wiring across to the existing or a new 24/7 consumer unit? Then run new secondary lower current Economy 7 wiring to each new storage heater from the Eco7 side of the meter.

EssexHebridean

When we had our quantum installed in the flat, the additional of the extra spur for the 24 hour supply cost almost nothing in the grand scheme of things. I'd strongly recommend getting the second feed installed with the heaters as it removes one huge variable - that of operator error - from the use of the heaters. Our install of the Quantum was a direct replacement for a very old (ancient!) Creda unit which ran on the E7 feed only - so the new heater made use of the existing E7 feed, and simply required the additional wiring for the 24hr supply which powers the screen and allows for the daytime use of the small heating element, as I recall. 

I do believe that Quantums can make a substantial difference to someone's heating bill purely on the basis that they will provide heat when it's required, rather than the person having the need to use "top up heating" on an expensive day rate. I'm not convinced that £2000+ isn't rather over egging things, though.

As for metering - our storage heaters - including the Quantum - ran perfectly cheerfully on a standard old style meter. No issues at all. If the current installation is NSH's, then the existing meter should be perfectly god to run a replacement installation of Quantums so far as I know. 

ch_152

I'm interested to see where you end up with this @cam269

I moved into a property on E7 with storage heaters in Jan. I used the old storage heater over the winter/spring but am looking to replace soon before this winter. And also looking at the Quantums.

I'm on Octopus. I asked for a smart meter for months before getting one a few weeks ago. Admittedly, I never called. Prior to that I had a traditional day/night rate meter. 

markin

ch_152 said:

I'm interested to see where you end up with this @cam269

I moved into a property on E7 with storage heaters in Jan. I used the old storage heater over the winter/spring but am looking to replace soon before this winter. And also looking at the Quantums.

I'm on Octopus. I asked for a smart meter for months before getting one a few weeks ago. Admittedly, I never called. Prior to that I had a traditional day/night rate meter. 

If the loft has been topped up in the last 10-50 years years you may get away with just upgrading the main living room, And check the old ones for any broken parts, heating elements are a £10 part.