Off peak storage heater charging duration

That may not be particularly economical. Any usage between 07:00 and midnight will be billed at peak rate. A water tank could take 5-10 kWh to heat up from cold, depending on the temperature it’s heated to and how big the tank is. 10 kWh at peak rate costs you almost £3. If you were to switch the immersion heater on at midnight and off in the morning, it would cost less than £2. A reasonably well insulated tank should stay hot for at least a day. 

The short offpeak periods were part of your old Flex heating deal, which no longer applies. The schedule was set by the RTS, and managed by the electricity network operator (UK Power Networks). They have been replaced by one single offpeak overnight period. Your meter now switches power on to the heaters at midnight. If you want to restrict how much electricity they draw, turn down the input dial.

Please don’t rely on the £p figures from your IHD; they are only a guide, and the big numbers you see are instantaneous values. If you boil a kettle for tea, it will show something like £0.90 per hour. Because the kettle is only working for a couple of minutes, the cost of boiling it will be only something like 10p. Get used to looking at the kW figures in order to spot higher-than-normal consumption from time to time, e.g. when you turn the immersion heater on.

Your online account will tell you far more about your usage and what it’s costing than I can guess at.

Firedog - thank you for explaining about the old Flexi deal which no longer applies, as it was controlled by my Radio Teleswitch Service (RTS) which was removed with the new smart meter installation.

That explains why my previous x2 Off Peak charging periods are now only one period at the start of my Off Peak period - midnight.

What stops my Dimplex storage heaters drawing Off Peak current ? Is it a thermostat in each heater or unlikely the end of the Off Peak period at 7am ?

In addition, what is the schedule in the Auxiliary Load Control Switch (ALCS) ? You mentioned it in the attached post a year ago. You suggested to the OP that although their smart meter was switching from Peak - Off Peak - Peak at the correct times their ALCS schedule might not be right.

Thank you.

Both. The heaters are fed from a circuit separate from everything else (although I would normally expect the water heater to be on the same circuit).  This makes sure that heat storage equipment is never using power at the peak rate, because this ‘switched’ circuit is only live during offpeak hours.

If a heater reaches capacity or the maximum temperature set on its thermostat, it will stop drawing power even though the offpeak period hasn’t yet ended.

The normal arrangement is for the load control switch to close at the start of the offpeak period and open at the end of it. The example you saw was of a switch that wasn’t doing this, which is why I suggested the customer ask for it to be corrected. In that case, heaters were charging during peak periods, costing more than they should. As far as I can tell, your control switch is operating just as intended, so there’s no need for any change. 

I’ll say again, just in case you missed it: all electricity you use during the offpeak period will be billed at the offpeak rate, and all electricity you use in peak hours will be billed  at peak rate. It no longer makes any difference what the electricity is used for, as it may have done on your old plan. This is why it’s important to aim not to run any power-hungry equipment - like your immersion heater - during the day.  

Firedog - thank you.

Been on to OVO chat. There is an Economy 10 tariff with Off Peak times - 12am-5am, 1pm-4pm, & 8-10pm GMT.

It seems to be cheaper Peak/Off Peak/Standing Charge than my new Economy 7 tariff which is Off Peak midnight - 7am.

Would my storage heaters potentially charge up in each of the 3 Economy 10 Off Peak time periods ?

My situation with a new smart meter is somewhat confusing.

New Economy 7 tariff Off Peak - midnight - 7am.

Before smart meter I had a now redundant RTS controlled tariff which switched on my storage heaters for only 2 hrs a night - 10.30pm-11.30pm & 4.30am-5.30am. Now my smart meter charges up my storage heaters between midnight - 7am. From 2 hrs to up to 7 hrs. Will this increase the Off Peak element of my total bill ? (I appreciate that it is not just charging time but how much current is used as well).

In addition I now have to wait until midnight to manually turn on my immersion heater to get Off Peak rates instead of 10.30pm as before my new smart meter. It doesn't have a timer on it.

I see the need for a smart meter - but I thought that when getting a new smart meter I would have roughly the same bills & not have to turn on my immersion heater until after midnight.🤔🤔

That sounds unlikely. Where you live, the peak/offpeak unit rates for Economy 10 are currently 26.98/20.90 p/kWh, as opposed to 27.79/18.63 p/kWh for Economy 7.  Note that it’s significantly more expensive to pay on receipt of bill rather than by Direct Debit.
  

Yes, in just the same way as they now charge during the Economy 7 offpeak period. 

I did ask earlier, but is your immersion heater wired on the same circuit as the storage heaters? That would be the normal arrangement with any peak/offpeak arrangement, but it may have been different under the Flexiheat plan. 

Is there an indicator by the immersion heater switch to show when it’s heating up?

If it’s wired together with the storage heaters, it would have power during the same offpeak period. Depending on how big the tank is, and how well insulated, it may be enough to allow it to heat up fully one night; this could give enough hot water to last for two or three days. The thermostat will switch the power off when the tank has reached its target temperature. Again, you’d have to experiment. 
  

My immersion heater can be switched on at any time of day so it can't be on the Off Peak only circuit. Its electricity used in the Off Peak period presumably is charged at that rate even though it isn't on the Off Peak only storage heater circuit ?

It has a thermostat & it is possible to hear when it is no longer heating up.

The OVO chat lady mentioned an Economy 10 tariff (I had signed in so my having a smart meter should have shown up) but the OVO website stated that there is no Economy 10 smart meter. My smart meter would have to be replaced by a non smart Economy 10 meter & I would have to pay an installation charge.

If you have Economy 7/9/10, then ALL electricity usage during Off-Peak hours is tracked as Off-Peak and charged at the cheaper rate, regardless of what’s using juice.

Likewise, ALL usage at Peak times is charged at Peak rates. Please make sure to factor this into your usage patterns so you don’t accidentally rack up huge bills. If memory serves, OVO wouldn’t be able to reimburse/refund you nor offer a discount if you ended up using high power stuff at the wrong times.

Blastoise186 - thank you.

Yes, that’s how it works. It doesn’t matter how an appliance is wired up or what it’s for: if it’s used during offpeak hours, its usage will be billed at offpeak rates.

I suggest you try just one night switching the immersion heater on at five past midnight, and switching it off again the next morning. It will have heated up to its target temperature and switched itself off. Then note how long the hot water lasts for. 

I think you must have found an old article. OVO has been installing smart meters configured for Economy 10 for a long time. It’s not certain that it will be quick or easy to re-configure your present meter just now, though.

You were concerned that you were now getting seven offpeak hours instead of the two you were getting before. Economy 10 gives ten hours of offpeak power. What changed your mind?