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December 12, 2018
Solved

How do OVO convert gas units to Kwh on a smart meter?

  • December 12, 2018
  • 24 replies
  • 5062 views
The calorific value is needed by the Smart Meter to convert the volume of the gas to the energy produced by the gas Kwh. As this varies on a daily basis what value does the meter use?

Is this the same value as used by the bill?
Best answer by Beth_OVO

Updated on 21/08/25 by Abby_OVO

 

Great question to ask. You may have noticed your smart meter will show your gas readings in both volume (meters cubed or m3) and in the kWh units that are charged on your monthly summary.

 

In order to covert an m3 unit to kWh, we need to carry out a complex equation which involves taking into account the calorific value of gas. As this can change month to month, the calorific value we use to calculate your charges may differ slightly to the one used by your meter, which uses a set value of 39.2. As the calorific value changes so often, it's not practical for the meter to be constantly updated with it. However your monthly summary will use the up-to date calorific value that you can find online here.

 

When submitting your meter readings manually on your online account or OVO app (download for Android or iOS), you’ll only need to send us the m3 figure and we’ll do the rest. Find out how to read your meter reading manually here.

 

Hope this helps :slight_smile:

24 replies

BPLightlog
Super User
Super User
January 18, 2023

Hi @KayCommis have you checked your meter readings? If so are these actual or estimated? (They might still be estimated at some times even with a smart meter). This might be the reason. Otherwise, depending on your heating, it was much colder during that time so your heating probably use more

Bring me Sunshine ~ E&E {Solar PV, Battery Storage, Hybrid EV, ASHP and Home Assistant automation}
Newcomer
January 18, 2023

Hi @KayCommis have you checked your meter readings? If so are these actual or estimated? (They might still be estimated at some times even with a smart meter). This might be the reason. Otherwise, depending on your heating, it was much colder during that time so your heating probably use more

But the app tells me about 2 days later what I used on the day.... so for example, on the 13th of the month the app will tell me my exact daily use of 11th of the month. 

 

I thought smart readers meant that I don't need to send meter readings anymore?

BPLightlog
Super User
Super User
January 18, 2023

Hi @KayCommis have you checked your meter readings? If so are these actual or estimated? 

 

I thought smart readers meant that I don't need to send meter readings anymore?

Generally yes but they can occasionally lose signal so it’s worth just checking what it says against your meter readings

https://account.ovoenergy.com/meter-readings

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Jeffus
Rank 20
Rank 20
January 18, 2023

So here is my electricity meter reading page for example. If it is working perfectly you will see a reading every day with the word Smart next to it. 

 

Newcomer
June 13, 2024

My Liberty EG4v10 meter was installed in 2015. So an early one.
Can anyone tell me if the original readings were in cu ft or cu M?
Thanks.

Blastoise186
Super User
Super User
June 13, 2024

Hey @carmelsdad26 ,

Sure thing! That meter - and all Smart Gas Meters - uses Metric measurements, so it’d be Cubic Metres. The last known install of an Imperial Gas Meter was something like 20+ years ago at this point which would have been long before Smart Meters were even being designed.

Hope this helps!

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Newcomer
February 7, 2026

I’m submitting meter readings manually each day after the central heating goes off at night so they reflect gas usage that day. Gas usage that appears in my account bears no relation to what is submitted. Why? 

Nukecad
Super User
Super User
February 7, 2026

I used to have to send in readings for gas, and it can be confusing for a couple of reasons.

the system of daily usage and ‘live balance’ is set up for smart meters.

So when you submit a manual reading ot is attributed to the previous midnight - the midnight at the start of the day that you submitted it. (Because that's basically what smart meters do, usage up to midnight each day is sent/collected the next day).

Then with gas there is a question of how long that takes to get reflected in the figures that you see in the usage chart online or in the app.

To start with those figures will be ‘guesstimates’ but they will change later as your readings are taken into account and the Calorific Values for that day known.

Your reading is in cubic metres which has to be converted into kWh by multiplying it the CV (and a conversion factor).

It all means that the online usage figures for gas can take a while to change from estimated to actual.

But in the end it's what your monthly billing says that matters.

 

I said, Hey - Watts going on.
Rank 12
February 8, 2026

Your gas usage on your bill is charged in kWh, not in the units shown on your meter.

You can, however, approximate the conversion from the units used according to your meter to kWh. The approximation depends on the units measured by your meter (it will be shown on the meter) as m³ or ft³.

To approximate gas units to kWh in the UK, multiply metric (m³) units by 11.2 or imperial (ft³)  units by 31.7.

For instance, I have used about 2 units on February 6th. My meter measures in m³. So, using the approximate conversion 2 X 11.2, I have used about 22.4 kWh of gas. 

This is a useful “guesstimate”.

Abby_OVO
Community Manager
Community Manager
February 9, 2026

Hey ​@Lindsay23 

 

I’m glad to see a couple of our community members have already stopped by with some really helpful advice here, I hope you’ve found that helpful.

 

As they’ve suggested, the bill each month is what we’ll have calculated and you’ll be charged, the live billing system, especially while traditional meter readings are being submitted, will simply catch up and that reading will be attached to a single day, rather than the time it was submitted in the day.

 

I do have a few questions here just to gain some clarity, which section of the account are you looking at when you see this? Can you see the meter readings you’ve been submitting on the meter readings page, do they match what you’ve been submitting? You should be able to view a full rundown of all the meter readings you’ve previously sent us by clicking ‘view reading history’. 

 

I’m also wondering if your bills have been using the meter readings you’ve been submitting, are those accurate? These are where your actual usage is broken down, and these should be accurate. If you’d be able to share some more detail, it will help us better understand if there’s an issue or if it’s just the live billing system.

 

The following topic may also be helpful here:

 

 

And if you’ve not looked into one already, we’d definitely recommend having smart meters installed - that way we can calculate your usage even more accurately with half hourly readings. Check out the topic below for more:

 

 

Let us know how you get on, or if you could provide some more information, we’ll try our best to help.

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