I’ve just received my latest gas bill and I’m really confused by the usage.
My meter reads directly in kWh, and the readings were:
2 May: 73367
15 May: 73584
18 May: 73614
That’s a total usage of 247 kWh, but my bill says I’ve used 2776.16 kWh, and I’m being charged £161.35 before VAT.
I’m not sure where the 2776 kWh figure is coming from when the difference between my meter readings clearly shows just 247 kWh used. Has anyone else experienced something like this or have any idea what could be going on?
Would appreciate any advice – thanks!
Best answer by Nukecad
Updated on 29/05/25 by Ben_OVO
Gas meters do not, can not, read directly in kWh.
You cannot measure gas directly in kWh because the composition of the gas, and so how much energy (kWh) it gives when burned, changes all the time. That is known as the ‘Calorific Value’ of the gas - and it is monitored daily and the figures published.
Instead gas meters read the volume of gas consumed in cubic Metres (or cubic feet if it’s a very old meter).
That is then converted to kWh using a standard calculation factor.
The conversion calculation used is given on each bill that you get and is:
Your readings above are showing 73614 - 73667 = 247 m3 used so depending on the actual Calorific Values for the days in question around 2776 seems correct. However it does also seem quite a high usage for the time of year.
Edit- Firedog has identified what is probably happening here, if you have been sending in the ‘estimated kWh’ by mistake instead of the m3 then that could explain it.
To find the calculation shown above you’ll need to download your bills and check page 3 of the statement. Here’s a handy guide that shows you how to download your statements:
Most gas meters measure in cubic metres (m³), not kWh. Only a few leftovers from last century still measure in cubic feet (ft³). The actual figure used for billing is the one shown as m³.
x 1.02264 adjusts for the temperature and pressure of the gas on delivery compared with that when the calorific value is measured; x 39.6 is the calorific value, CV, used to convert m³ of gas to MJ (megajoules, million joules) of energy. The CV changes from day to day 1MJ = 1 MWs = 1000 kWs = 1000/3600 kWh]
Some meters will have an option to display usage in kWh, but that is just an approximation using an average calorific value to convert from cubic metres. The actual figure to be used for billing is the one shown as m³. If you have been submitting the kWh figures from the display, your bills will have been about 11x too high. Please check the meter reading history in your online account to see whether this is the case. A photo of the meter itself clear enough for the display to be legible posted in your reply would help nail this down for you.
You cannot measure gas directly in kWh because the composition of the gas, and so how much energy (kWh) it gives when burned, changes all the time. That is known as the ‘Calorific Value’ of the gas - and it is monitored daily and the figures published.
Instead gas meters read the volume of gas consumed in cubic Metres (or cubic feet if it’s a very old meter).
That is then converted to kWh using a standard calculation factor.
The conversion calculation used is given on each bill that you get and is:
Your readings above are showing 73614 - 73667 = 247 m3 used so depending on the actual Calorific Values for the days in question around 2776 seems correct. However it does also seem quite a high usage for the time of year.
Edit- Firedog has identified what is probably happening here, if you have been sending in the ‘estimated kWh’ by mistake instead of the m3 then that could explain it.
To find the calculation shown above you’ll need to download your bills and check page 3 of the statement. Here’s a handy guide that shows you how to download your statements:
I don’t know about calorific values etc. Obviously a few very well educated peeps do and only add to my confusion. I would have my meter checked incase I had a leak, especially as we’ve had such good weather, you gas usage is likely for heating water. Or have you had lots of showers recently? sorry I can’t be of much help, but if it happened to my bill, I would contact OVO for an explanation. Should it happen on my bill I wouldn’t be able to pay. 😬
Some meters will have an option to display usage in kWh, but that is just an approximation using an average calorific value to convert from cubic metres.
Here’s a common type of gas meter, capable of showing both m³ consumed and the approximate equivalent kWh:
@calvinm518 welcome to the Forum, and thanks for your post.
@Nukecad and @Firedog have explained this well - unfortunately it can only be explained as it is, and it can be a bit confusing. If you wanted to see the conversion information and calculations for gas yourself my advice is to download one of your bills.
When you’ve got the statement open, scroll down to page 3 and you’ll see the info on how we calculate your gas to KWH’s. There’s also a link that provides info on calorific values:
That’s the same sort of meter as you could see in the YouTube video I posted a link to. If you press button 9 once, you will see first the word VOLUME followed by the volume measured in m³. Only if you press again will you see the approximate conversion to kWh. It’s the m³ figure that should be submitted to the supplier.
The meter can only measure volume; its internal computer converts the figure to an approximate no. of kWh for your information only. The conversion is only approximate because the meter doesn’t know the calorific value of the gas passing through it.
Yours is a smart meter, installed by E.On some years ago. It should originally have sent the volume readings to the supplier automatically, but that may have stopped when the supply was switched.
Did you check the readings on your online account? When you opened your account with OVO, you will have provided an opening reading. If that was a kWh figure, you will have been overcharged a great deal ever since. Each m³ equates to about 11.2 kWh.
I finally figured out what’s gone wrong with my bill. When the supply switched over, there was some sort of issue and my gas meter stopped connecting properly. During that time, OVO asked me to submit meter readings — which I did, but I submitted them in kWh rather than m³ because that’s how it showed on the app.
This has now led to a huge error with my billing — I’ve been charged almost 10 times what I’ve actually used.
I spoke to one advisor at OVO who understood what happened and explained that the fix is simple: just convert the kWh readings I submitted back into m³, using the same method OVO uses to convert m³ into kWh. Unfortunately, I had to end the call early, and since then I’ve spoken to 8 different advisors (phone and chat), but none of them seem to understand what I’m trying to explain — they keep saying the bill is correct when I know it’s not.
I’m now stuck with a massively overestimated bill, and I’m getting nowhere fast. Has anyone else dealt with this kind of thing? Or can someone from OVO support on here help get this sorted?
Any advice would be massively appreciated — really stuck here!
OK, that’s what we suspected. What you need now is to create a long list of all the meter readings that have been used for billing. You should be able to find them on your online account - they’re there in the meter readings history, and also on each bill. There should be a recognizable sequence of increasing numbers culminating in the latest, to which you can add today’s.
I can’t be certain, but I think the kWh figures are arrived at by using an average CV of 39.5 MJ/m³. That means that each of those readings - rising up to a number like 73xxx. If you know your way around a spreadsheet program like Excel, it’s really easy to convert them all back to numbers like 73000 > 6505 just by dividing them by 11.2206
1.02264 x 39.5 ÷ 3.6 = 11.2206
So the figure of 73614 kWh from your last bill becomes 6561 m³.
You could then present the monthly figures with dates to Support and ask them to arrange for your account to be rebilled all the way back to the first kWh figure you submitted after the meter stopped doing it. To illustrate the mistake you’ve been making, you could take photos of the meter showing first the m³ figure and then - after pressing 9 again - the kWh figure. If you use the web chat option when contacting support, you’ll be able to upload photos and other documents, like your list of readings as submitted and as they should have been.
It appears that with Firedogs comprehensive explanation and understanding of the incorrect conversions that have happened since you switched to OVO I’ve been extremely fortunate to not have had any problems with OVO since they took over from previous supplier. I have had my Smart meters a few years now & no problems thank goodness. If I should have a problem I can’t sort with customer service peeps I hope Firedog and all the other very knowledgeable peeps on here, are able to help explain, so I can understand. I’m not the sharpest pencil in the box, but even I get the gist now of Firedogs explanation. Good luck getting it sorted with customers service agents and resolving the discrepancies
Chris
P.S Hopefully you’ll get a nice large refund. Treat yourself it’s savings you didn’t know you’d made. Unfortunately you haven’t earned interest but that’s incidental now Just get your refund. 👍
Thanks @Firedog for all your great info here, and @calvinm518 I’m glad to hear you’ve got to the bottom of things! Don’t worry, this is easily rectified 😁.
Hopefully the opening readings used following the switch of suppliers are accurate, and it’s just the readings given to OVO since switching that need changing. All you need to do is get in touch with Support. If you explain the situation and give them a photograph of an up to date reading they’ll be able to get the billing amended. if the worst comes to the worst, and the opening reading is also incorrect, this can be resolved through a process called a Read Dispute.
let us know how you get on!
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