Moving from THTC to Economy 10. Will the new smart meter charge storage heaters during off-peak periods only?

Hey ​@Lecky ,

By default the upgrade would be to Smart Meters so everything would run locally.

What I can say is that they’ll be set to only allow your Storage Heaters to run during Off-Peak hours which is similar to how things work now. The biggest change however, is that during Off-Peak hours, ALL your usage is charged as Off-Peak so you’ll want to take advantage of that.

Hope this helps, let me know if you have more questions.

Hello ​@Blastoise186 

My apologies. I am new to this forum and did not realise that I could respond to your reply specifically. To make amends I copy my reply below.

Many thanks for your response.

I shall ensure that most of the energy guzzlers (tumble dryer, washing mashine, water heating top-up, etc.) are unleashed only during the off-peak hours. And, I understand, whereas the storage heaters’ ‘Comfort’ and ‘Boost’ facilities could be (with THTC) set to come on any time during the full 24 hour period at the off-peak rate, any settings outwith the three Economy 10 off-peak periods will now be charged at peak rate by the new ‘smart’ meter. I shall be reprogramming the storage heaters to minimise their use outwith the off-peak periods.

I am still awaiting an assurance from OVO that an appropriate 5 terminal SMETS2 will be installed which will be able to ensure that the automatic switching of the heater charging circuits will take place during off-peak hours only. Why OVO has not provided this information is a mystery and concerns me. Is there an undisclosed technical or locational problem? Surely not a state secret. In this instance silence is not golden.

I see.

Bear with me as I think we’ve got a way to get that advice for you. This may take some time but I’ll be back when I can.

Thank you for taking the time to annotate your photo - it makes everything so much easier to understand. It might have been better to make sure that the image is clear; it’s often the case that it’s important to be able to read the markings on the various devices and the display on the meters.

While we’re waiting for the authoritative response to your enquiry, I can say that no-one can say beforehand what type of meter will be installed. There are two or three different types currently being installed in Scotland, and it just depends what type the engineer happens to have in his van what type you get. We have heard of recent supply problems with one type, but they all adhere to the strict SMETS2 specification.

Since your storage heaters are currently on a restricted circuit, and the supply is neatly mounted in the meter cupboard, the installation engineer will normally replicate the restricted circuit by connecting it to the switched port of a five-port dual-rate meter, but it’s also possible to use a four-port meter with an external 100A contactor instead of the one inside a five-port model. This would normally behave in exactly the same way, ensuring that the really power-hungry stuff is only energized at offpeak times.

I’m sure you understand that there’s no 24-hour reduced rate for heating any more. With the new smart meter, electricity is billed solely according to when it’s used, not what it’s used for. This means you’ll have to learn to be circumspect with, for example,  direct heaters like panel heaters, fan heaters or radiators.

Hello Firedog,

Thanks for your insight.

I am aware that there will be no 24 hour off-peak storage heater output control under the new system. As I commented previously, I shall be reprogramming the storage heaters to minimise their use outwith the off-peak periods.

What I find nonsensical is the seeming inability of OVO to ensure that the appropriate smart meter for each and every property visited is available for installation by the engineer. Anything else amounts to ‘lucky dip’. 

I need OVO’s assurance that our storage heaters will be automatically charged SOLELY during the three Economy 10 off-peak periods.

With the astronomical cost of electrical energy, surely such an assurance should be immediate and definitive.

I‘m afraid you may have misunderstood what I wrote. As far as I can make out, Quantum series G storage heaters have two supplies, each controlled by a switch on the wall. One of them is the restricted (‘switched’) supply providing the power to charge up the heater core during offpeak periods. The other is a much leaner 24-hour supply providing power to the heater’s controls, its fan and in some cases its booster element. Your statement here (“… there will be no 24 hour off-peak storage heater output control under the new system ...”) doesn’t seem to be accurate. 

If the meter engineer is able to, he will ensure that the charging circuit for the storage heaters (and possibly for a main water immersion heater) is powered only during offpeak periods. If there are wiring changes needed beyond the meter cupboard to make this work, you’d have to engage an electrician to carry them out. I can’t see from your photo that this would be necessary.  

Just to keep you in the loop…

We’ve asked an expert to swing by and take a look at the thread. He might be able to swing by in the next couple of days if he’s not too busy, so please keep an eye out!

Just to add to this thread I have a similar issue in one of my flats. I am N Scotland with THTC.

There are 3 fuseboxes:

1) Normal house sockets, cooker, lights etc etc

2)3 Panel heaters, focus point fire, hot water Boost

3) One storage heater, hot water tank.

Previously 1) normal rate 2) and 3) offpeak with 3) being switched on and off over 10 hr period)

It would appear now that 1) is normal rate and 2&3) are offpeak only coming on during the 10 hours allocated for heating. Meaning we have lost heating the flat for anytime outwith the allocated 10hr window. Which obviously is not ideal.

Given there is only 1 storage (and HW tank which Im looking at fitting an instant HW heater in the kitchen instead as dont need to heat up a 100l tank just for that), I am thinking I am going to be better to ditch offpeak. When all the heating was on offpeak it was worth it, but now now. Unless you are saying that the WHOLE flat becomes offpeak during the allocated 10 hours?

That is correct. Unlike many of the legacy RTS Tariffs such as THTC, E7/9/10 switch the entire supply between Peak and Off-Peak rates, so everything will be charged the same rate at any given time of day and not just heating/hot water.

You can also boost the heating/hot water whenever you want if needed - but you’d be paying Peak rates if you do so outside of Off-Peak times.

Hello ​@rayshields 

It is my understanding that, whereas the Standard (peak) rate applied to all non-heating related circuits at all times over each full 24 hour period under the THTC system, with Economy 10 ALL electricity used during the 10 hour (3 + 4 + 3) off-peak periods will be charged at the off-peak rate. Therefore, arranging (whenever possible) for energy guzzlers (e.g. washing machine, tumble dryer, cooking appliances, top-up immersion heater) to be used during the Economy 10 off-peak periods should result in cost savings.