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What's the equation to convert gas meter readings into kWh?


Does anyone have the equation to work out the KWH from a meter reading for both gas and electric. Please.

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Best answer by nealmurphy 16 March 2022, 17:04

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Updated on 28/07/23 by Abby_OVO

 

As mentioned below, the calorific value of gas changes every day and can range from 37.5 to 43.0. To find out calorific values used to calculate your charges you can visit: www.nationalgridgas.com/data-and-operations/calorific-value-cv 

 

 

 

Hi @Johnnyhornet 

First the easy one. The electricity should be measured in kWh on the meter. So to work out how much you’ve used since the last reading you simply take the old reading away from the current reading on the meter.

Now for the trickier one (science books at the ready)…

Gas meters can measure usage in cubic feet or cubic metres. If yours is measured in cubic feet then multiply the value by 0.0283 to get cubic metres.

The volume of a gas is dependent upon pressure and temperature and therefore varies. The volume of gas measured by the meter is adjusted by multiplying by a correction factor to take account of the temperature and atmospheric conditions. The correction factor used will be shown on your gas bill (e.g. 1.02264).

Next, the volume needs to be converted into a calorific value (CV) which is a measure of the energy released when a given volume of gas is completely combusted. This depends upon the gas’s composition. The CV usually ranges from 37.5 to 43.0 MJ per cubic metre. The value used should also be on your bill.

Finally. the thermal energy can be converted into kWh. 1 Watt is 1 Joule per second. 1 Joule is 1 Ws. 1 kWh is 1000x3600 Joules = 3.6 MJ.

So divide the CV by 3.6 to convert MJ into kWh.

There will be a test next week, so don’t forget to revise.

 

Many thanks

Please help to understand this readings.
Our meters are reading in meters cub but we pay for KW 
How the meters cub are converted in to the KW and how much is actual a unit that is read on the meter.
Thanks

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This website has a conversion calculator https://www.theenergyshop.com/guides/how-to-convert-gas-units-to-kwh

I am interested in solar panels at the moment so am looking to work out kwh usage.  I can calculate kwh and make and estimate for the CV.  But I cant for the life of me get a value near what my usage is calculated at by OVO  How can I find out whether OVO have my gas metre readings as a cubic metre or cubic foot measurement?

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Hey @Gertie !

I can help with that. If you don’t mind, please can you post photos of your gas meter? I’ll need to see it in order to figure this one out. :)

Its a cubic foot meter Apparently listed as imperial meter. No. 021005

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Assuming that’s a meter reading, I calculate roughly 664988.1877 kWh. But this isn’t going to be perfect as I don’t have the exact formula to hand.

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There’s a site I’ve found that offers this service, @Gertie - theenergyshop have a page for this here

 

Can I ask what other factors you’re looking at when looking into solar PV panels in your home? Need advice from our solar panel members?

Hi all, can anyone advise, due to all the publicity around energy I have been looking at my bills in more detail and It appears we are spot on as average for electricity in a 3 bed house with two people but our gas consumption yearly is averaging out at 30000 KWH when average is around 12500. I appreciate not every home will be exactly the average but this is 2.5 times average which seems excessive. We have an old 1990 imperial gas meter in ft3 when I check the govt website for calculating this to KWh it does state that some older meters provide readings in cubic feet and not always 100 cubic feet. Could this be why as my supplier is using the calculation with x 2.83 and not 0.283 as it states on the govt website and a few other energy websites. When I calculate my readings using 0.0283  our average gas KWh is around 11500KWh which is more like the average. My supplier refuses to investigate, would anyone know how to confirm what readings my meter is providing, we have a combi A rated boiler, insulation double glazing and cook with electric. Only two of us so a shower/ bath each every day central heating not been on for months 

Thanks in advance

Mary

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Hi @MaryH 

What you have described sounds logical.

Are you able to post a photo of the dial part of the meter so we can see what the readings look like?

 

I have the photo can’t seem to attach it 🙄 I select it and add but it disappears 

 

Managed to attach , thanks for replying 

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Perfect. 

So for this type of meter you would ignore the numbers in red. This reading would be 5341.

Does this order of magnitude correspond with the readings shown on your bills?

More info on reading various types of meters is here:

www.ovoenergy.com/help/meter-readings

Hi thanks for offering I g back to me, yes that is what we use to submit readings eg I submitted a reading last week it was for 71 days of which we were on holiday for 15 of those so gas actually used for 56 days. The units used were 103 and when the supplier used the 3.8 calculation that equated to 3278 KWh for the 56 days and that’s only shower’s no heating. I believe when heating is on KWh is around double. I have spoken to people who have readings of around 3000 KWh in winter for two months with heating running hence why we are so concerned at using approx 30000 per year. We are fortunate right now we are on a fixed rate until 31st October but then our cost will increase dramatically and if this calculation of 3.8 continues we will be charged in excess of £5500 per year for gas alone surely this can’t be correct.

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Hi @MaryH 

I don’t have gas any more myself, but hopefully someone else can check the thought process.

@Blastoise186 who’s best to talk gas here?

I’d suggest getting in touch with your supplier to confirm what units they are using. Or if you are happy to post part of your bill with the calculations on and any personal information removed then we can see if there is anything obviously wrong.

 

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I just ran your meter reading in that photo through a calculator. It came out with 1565.29kWh. However, I’m almost certain that your gas meter has gone round the clock at least once, so it came out at 4495.71kWh if I calculate based on 15,340 Cubic Feet.

However, there is another problem. Your gas meter appears to have an expired certification and has therefore reached the end of its service life. It’s long overdue for replacement - Schlumberger hasn’t even made any gas meters for over a decade by the looks of things!

I’d recommend getting your gas and probably electric meters booked in for replacement, which will have to be for smart meters. Not only does this mean you’ll be billed based on a gas meter running in Cubic Metres rather than Cubic Feet (which is way easier to calculate!) but you won’t have any of this confusion anymore.

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I think there may well be an issue with the meter. If your readings have gone from around 5238 to 5341 (using your photo for the latest read) then that is indeed a lot of gas in such a short time over summer. As @Blastoise186 says, if you are able to get it replaced with a new meter I’d do this and also highlight the potential anomaly to see if this can be investigated. 

Thanks again. I have been in touch with them and a complaint is logged but they refuse to even consider that my findings are correct and won’t budge I am waiting on a formal response from them as I need that before I can go to ombudsman. They have no other reason why it may be so high they have been so unhelpful. I will try and upload a bill

mary

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Hi @MaryH,

 

Welcome to the OVO Online Community. 

 

This is a really interesting discussion and great to see our community members giving some tip top advice. 

 

However, there is another problem. Your gas meter appears to have an expired certification and has therefore reached the end of its service life. It’s long overdue for replacement - Schlumberger hasn’t even made any gas meters for over a decade by the looks of things!

I’d recommend getting your gas and probably electric meters booked in for replacement, which will have to be for smart meters. Not only does this mean you’ll be billed based on a gas meter running in Cubic Metres rather than Cubic Feet (which is way easier to calculate!) but you won’t have any of this confusion anymore.

 

You can book in a free smart meter exchange here. There is also lots of helpful information and resources available on the benefits of smart meters and how they work on the forum:

 

 

What is the formula to convert units to Kwh?

 

 

If your usage does appear high there are a few different factors that may be responsible from a faulty appliance, an old boiler or a meter clocking to much consumption. 

 

We have a really helpful guide here:

 

 

Hope this helps. 

Hi all, thanks for taking the time to respond

Blastoise I appreciate your response and I will certainly look to replace the meters once I get all of this resolved. I’m not sure what you mean when you did the calculation that came out at 1500kwh did you use a different calculation from x 2.83?

it is really high and we jus5 can’t understand it, I have jus5 haD a response from my supplier and they insist the meter is measuring in 100 cubit feet and the calculation is correct their answer is I must be using it more 😡 on what I have no idea as i said no heating heating and don’t cook with gas so 2 showers per  day for 56 days is nearly £90.

They are stating the 0.0283 calculation is only used if I submit 5 numbers on the meter readings which I don’t understand, I just feel it’s too much of a coincidence that my gas usage is “average” when I use the lower calculation. They have confirmed they won’t be investigating fur5be4 so at least I can now lodge a complaint to ombudsman.

I have attached a pic of the bill if anyone can think of any reason behind this I would really appreciate it thanks

 Mary

 

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Thanks for the info @MaryH 

I have to say, the calculation looks correct. The readings are only using the ‘white’ numbers and not the red numbers and so if in 100s of cubic feet.

Since the day of your reading on the bill and when you took the photo you’ve used 3 units which equates to 95kWh or £2.60. If that’s in around a week then if we pro-rata it it’s only 30 units over 70 days, so much less than what your billed usage is.

In Sherlock Holmes style here are a few possibilities (some less likely than others)

  • The meter is faulty
  • There was a gas leak (but latest reading appears to show reduced usage now)
  • The boiler used more gas for some reason (possibly when you were away?)
  • Your previous reading was wrong and should have been higher than entered (meaning more gas used up until June but less from June onwards)

I’d keep regular readings to see how it increases over the next week or so and if there are any sudden jumps.

 

Sorry I should have said that pic of the meter was taken on Monday 11th Sep to send to the supplier it’s now at 5345 so from 8/9 when I submitted the 5338 we have used 7 units in 8 days do you think that would be average with only a shower each per day?

I can see that would be slightly lower than the 103 units in 70 days or 56 days when we were using gas.

can you advise who is responsible for checking if the meter is faulty is that us or the supplier?

I appreciate you taking the time to look at this for me I can’t see how any gas would be used when we were away as nothing was switched on and nobody in the house, it’s becoming a real mystery 😲

 

Mary

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