Why does OVO over estimate the day or two difference between the actual reading and the estimate on the billing day?

  • 24 November 2021
  • 3 replies

Userlevel 2

I just received my bill for Oct - Nov, it is done on the 18th of the month. This month I gave my reading on the 17th, OVO go on to add a bit (estimate) to round it up to the bill day, the 18th.

I just sat down and calculated how much they ‘estimated’ and it is way off, in this instance we are only talking about 24 hours use, but the extra added is much higher than any reasonable calculation could reasonably add. For gas, they added 12 units and considering the actual reading indicates for this month we used a total of 58 units, about 2 units a day? The same goes for the electric, OVO added 30 units for approximately a 24 hours period, when the recorded readings show the usage this month to be 8-9 units a day. This affects our positive credit status, doesn’t it? I am willing to concede I may have got this wrong, my maths can be a little wayward. But if I am not wrong, then why do OVO not just use a simple percentage to estimate the excess since the readings were given?

Divided the given readings difference, by the number of days, to give a usage per day within the billing period.


3 replies

Userlevel 7
Badge +5

Hey there @Pierssy !

Hmm… That looks like the legacy billing system to me. Do you still use an OVO ID to login to your account? I don’t need to know what the ID is, just whether you’re using one - that helps me to know for definite which system you’re on.

While the new billing platform is custom built in-house by OVO’s sister company Kaluza, the legacy billing system is actually a third-party product that OVO purchased from another vendor back in the day. OVO doesn’t really have much control over the latter as only the vendor for that one can fix an issue like this.

My understanding is that a lot of these issues from the legacy system have been fixed in the new one, so this shouldn’t be a problem once you’ve been migrated over (the new one is a lot more accurate in general).

However, the Support Team will be happy to discuss this with you, as they might be able to optimise your Estimated Annual Consumption values to better match your actual usage and (hopefully) squash these estimates down a bit. It may also result in your payments dropping slightly at the next Direct Debit Check-In or when you come to renew. It’s definitely something that I’d recommend asking them about, as it may help to smooth things out a bit more effectively.

Either way, you’ll only be billed and pay for what you actually use, so the bill you get next month will technically “fix” the estimated usage for that one day and reflect it in the following bill. Technically, it could cause minor quirks in your credit balance, but it’s probably not too bad given that it would probably remain fairly stable anyway.

While Smart Meters can also resolve this even in Monthly mode, I can understand if you’re not ready to upgrade right now. I’ll drop the link here just in case you are interested, but feel free to hang onto your current setup in the meantime if you’d rather keep things as they are.

Userlevel 7

Welcome to the OVO online community, @Pierssy -


See you’ve already met one of our top volunteers around here, @Blastoise186 who’s given some great advice which might help explain why you’ve noticed the difference between the actual readings you submitted and those estimated readings that were generated the following day.


In case you wanted more information on the ‘Estimated Annual Consumption’ (EAC) figure that was mentioned we’ve got a great guide to this here.


We’d also second the recommendation to consider a smart meter installation - this really helps ensure that your billing is based on actual readings received from your meter rather than estimates generated on your billing date as well as offering some more great benefits.


Have you been submitting you meter readings on your online account? As @Blastoise186 we’ve been updating all our members to a new online account which should look something like this (your account should be updated shortly if it’s not already!):


Exact appearance may vary

One of the great features of this new online portal is the ability to calculate your balance on a daily basis - any time you submit a reading here you’ll notice your balance will update to account for the up-to date usage, a great way to check things following an estimated statement. We’ve got a full guide to help you get to grips with the way this works here.


Hope this information helps - Do pop back if you’ve got any more questions, we’re always happy to help here! 

Userlevel 2

Hmm… That looks like the legacy billing system to me. Do you still use an OVO ID to login to your account? I don’t need to know what the ID is, just whether you’re using one - that helps me to know for definite which system you’re on.


Many thanks @Blastoise186, It’s not really a huge issue, and yes I log in with an ID. Just odd that the top up estimate should be so wildly excessive. 

All the best