Why do the usage figures shown on my In-Home Display (IHD) not match those shown on the usage pages of my OVO app?

Gas or electric?

It turns out to be easier to track this stuff down for gas than for electric. But there are a few twists and turns along the way. I’ll be interested to see how Ovo answer this one…

;-)

For electricity, my understanding (in a nutshell - me? be brief??) is that:

half-hourly usage data come direct from the meter (via DCC) and relate to 30 minute intervals that all start within moments of the hour and half-hour (according to official time, UTC, which the Comms Hub has access to). The data are the same wherever you get them from, Ovo, Hildebrand, whoever you might authorise to retrieve them, because smart meter data is only available through DCC.

The daily usage values are all calculated as differences between successive daily meter readings (it would be better to call them nightly, because they’re taken close to midnight: the readings are listed by date if you look for meter readings, under “Account” in Ovo’s smartphone app, and are taken at the start of that day - they’re “opening” readings. BUT, meter readings are only ever available at the moment they’re provided. So if Ovo ask DCC for a meter reading at twenty minutes past midnight, they’ll get a reading that is different from what the meter register had held at midnight, twenty minutes earlier, and so the “daily” usage doesn’t quite square with that sum of 48 half-hourly usages that you’d hope it would agree with. But it will be close, usually, because any discrepancy only relates to a few minutes of usage, and that’s never going to be a lot of kWh.

So far as I understand it, *this* is the reason why you can never quite tie up HH usage data with monthly bills even if all the smart meter data are present.

If some smart data are missing, then we (or rather Ovo) get into the business of estimating values to fill in the gaps. And the place this comes in with a vengence is those “daily usage” values because, as I mentioned above, they are defined as the difference between meter readings taken on two successive days. And if the smart meter hasn’t provided both readings, well there’s a challenge and, to be quite honest, how well Ovo handle this has been a matter of some discussion in parts of this forum for a while now.

One test of all this would be for you to look at the smartphone app and see if any dates are missing in the list of smart meter readings around the time you have the discrepancy between 16.60 and 22.7 the daily usage should be identical (you can only check this to the nearest kWh because Ovo don’t share readings with any greater precision that that, except on the monthly statement) to the difference between the right pair of smart meter readings. If either or both smart readings are missing, then 22.7 is an estimate, and Ovo might have had to make it an overestimate to make up for an earlier underestimate.

As I said, there has been quite some discussion about Ovo and estimation…

With apologies for the lack of brevity,

Cheers

PS I shall reassure @Tim_OVO that it is not my intention to complicate this summary by dragging in the question of whether Ovo’s times might be out by 30 minutes but, be warned - anyone looking at the IHD and trying to tie those numbers up with the HH usage numbers that everyone gets from DCC will notice the error eventually.

PPS Apologies to anyone who still thinks that smart meters actually keep a historical record of meter readings, as opposed to “usage”. I’ve taken the bold step of asserting that THEY DO NOT DO THIS. Smart meters only store usage. The only way I’m going to retreat from this position is if someone comes up with a real live example of a stored meter reading (that some utility company uses) rather than merely pointing to the SMETS2 standard definition document and says, more or less “the standard says they do, so they do”. That’s not good enough - I want real hard evidence that smart meters store a history of readings, because I’ve never seen any.

PPPS (and why not?) The reason for the initial question, gas or electric, is that gas meters run on batteries, they do the absolute minimum, and that is to broadcast their meter reading only once every 30 minutes and this means that the daily and HH usage data do tie up after all, because there’s no room for a few minutes worth of discrepancy. It’s the full 30 minutes or nothing. In a good month, there are no missing nightly readings, and no missing HH usage data and they do tie up to better than a millionth of a kWh. (I’ve checked it, once. Actually, you can miss nightly readings during the month, because the error in usage for one day, arising from an error in the estimate for the closing reading at the end of that day is exactly cancelled by the matching error in the usage for the following day arising from the same estimate being used for its opening reading. It’s the opening and closing readings for the whole month that are essential, fairly obviously.)

If they have to, they estimate, yes.

Interesting that you saw that number change, and especially that it changed from something puzzling to something understandable - which must be a good thing: I don’t mind estimates being a little odd so long as that’s only a temporary state of affairs.

Cheers

Many thanks all for the info

Hi @Cantata 

I don't work for OVO or have access to your account. I am just a customer. A few of us help out with a few posts if we think we can. 

In case you didn't know

The usage page on the app doesn't include vat or standing charges. 

https://account.ovoenergy.com/usage

The IHD includes both standing charges and VAT. Your bill includes VAT and Standing Charges etc. 

Does this help explain any of the difference or did you already know this? 

Hope that helps

The costs on your IHD (in home display) for your smart meter include VAT and Standing charges.

The costs on the usage page on the website and app don't include vat or standing charges

https://account.ovoenergy.com/usage

So the costs on the usage page on the website and app will always be lower than you see on your smart meter. 

Does that help? As you say you may already have known that. 

Hi @Cantata 

The other reason is sometimes the tariff info on the actual smart meter is out of date. It may have got out of sync with your real tariff stored with your account. 

So ask the Support Team to send the SMETS Command "Update Tariff Configuration." 

That is definitely worth a try. This will update the smart meter in your home. 

If that doesn't work one of us can ask you a  few more questions to see if we can help you. 

Feel free to ask anything, there are plenty of customers that try and help out here. 

OK? 

Ah, thanks, I did wonder. I also hoped that the meter was right and OVO was wrong!! I’ll try and get hold of them on Monday I guess.

Hi @Cantata at the same time ask them to check your smart meters are setup for 30min readings. Some people only have their smart meters setup to automatically send a meter reading once a month. We have seen examples of this making it difficult for customers looking at their daily figures. They will be able to check and make this change if necessary. 

I moved in recently and have been charged twice the amount for bills. My flatmate called and they said they have a set amount they charge to cover future issues that is more than what is on the meter. Is this true? If so, where is that stated in their policies? I don’t want to pay for something I haven’t agreed upon in writing. 

In regards to billing, no security deposit was mentioned, just the surprise this morning when our bill was way more than what the meter had read, and it’s exactly twice the amount.

Not entirely sure about what a smart meter is, I’m assuming it’s the information linked to a display showing electricity/gas and price? I have that.
 

I’ll get back to you on the rest since the account billed is associated with a flatmate and not myself.