Smart Meter Monitor Puzzle

MsSED

When my gas central heating switches off or if it cuts out because it has reached the thermostat temperature, I have noticed that the Smart Meter IHD suddenly increases by between 25p and 30p about a minute later.  Does anyone know if this is because:

a) there is a time lag between the gas that has actually been used and the monitor display. or
b) the system expends more energy when switching off, or
c)  it is faulty.

If the answer is (b), then it would seem to support the old BG theory that it is better to keep the heating on.  Any thoughts would be much appreciated.

Alnat1

Gas readings are only updated every half hour, so each time the price updates on the IHD it calculates use over the previous 30 minute period. So if your heating had been off for 10 minutes you would still see the price move to show costs of the first 20 minutes of that time slot.

MsSED

... so if you see the IHD increasing by 1p at any time, then it must relate to the electricity, or what?

Scot_39

Electricity is updated much faster - several times a minute - iirc every c10sec

But if your looking at a split price for gas only - any chance any of your gas appliances still has pilot lights ?

MsSED

Yes, my gas boiler has a pilot light. Thanks for that suggestion. That said, I have only noticed these jumps when the central heating switches off since EDF changed their computer system at the back end of last year.

Scot_39

So is that 1p really every update just for gas ? - every 1/2 hr on ihd -  when hw and heating off ?

1p every 1/2 hour update
- 48p a day
- £175 pa.

At 7.4p - that would be 6.5 kWh per day, 2400kWh pa.

Which seems on the high side for many, a quick google for pilot light use does suggest that they could be upto that.  A translation comes up suggesting 594 to 2475 kWh pa.

You might want to look at the gas kWh on a slightly warmer day over a few hours to work out a truer running cost.

But then there was another poster a while back saying his was 6kWh per day over a 5 day test - so its not unheard of.

https://forums.moneysavingexpert.com/discussion/2746166/pilot-light-gas-usage


The other problem is it may not be a particularly modern boiler - so not as high efficiency - so could be adding even more in running costs.

In both cases literally burning your money.

But there not exactly cheap to replace either - and efficiency paybacks over n years whilst a great way of justifying the investment - it doesn't help magic up the money.


Re the lumps on readings - the IHD gets its data only from the meter, not from EDF themselves

Although any firmware updates to it - and even an increase in rates could impact say when rounding comes in - especially on the standby 1p thing.

But a change to EDFs internal billing systems should have in itself no impact on IHD.

bob2302

I don't know if this is typical, but on my IHD gas updates every 60 minutes. The figure of 30 minutes is the resolution of the data tables.

MsSED

Many thanks for all your helpful comments.