Gas Calculation - Maths errors

  • JimL's Avatar
    Level 5
    Since the switch from EON to EON-Next almost every monthly statement has contained a mathematical equation error when calcuating gas consumption
    Previously the error has been in the formula to convert meter units to Kwh:
    Pasted from my statement -9.3 × 1.02264 × 40.1† ÷ 3.6 = 106.4
    Using a calculator, it's easy to see the result rounded to 2 decimal places is 105.94

    Today I have received a statement with the following
    15th July 2022767.9 Smart meter reading
    15th Aug. 2022769.9 Smart meter reading
    Consumption2.1 Units (m3)
    A child can calculate the Consumption is 2.0 units - not 2.1
    I'm a very low user so the overcharges ar mere pennies. That's not the point!
    Has anyone else noticed these errors. Check your statements ver carefully to see whether you have the same isssue.
  • 37 Replies

  • Best Answer

    theunknowntech's Avatar
    Level 80
    Best Answer
    Well, if you need the Calorific Values for gas, I can get you that, piece of cake. https://mip-prd-web.azurewebsites.net/DataItemExplorer Help yourself! :)

    And there's a lot more data on there as well, in case you're curious.
    Just another guy passing by... The unknown tech way...
    Pete is an IHD Tariff Update Robot! 🤖 Anasa is a Giant Enemy Robot Spider 🕷 🤖 Hannah is neither! Need Customer service? click here! Replacement IHD Guide? Here it is!
  • Andy65's Avatar
    Level 46
    Hi @JimL

    The easier part to deal with is with what you've used. The Gas Meter sends readings to 3 decimal places, you can see this on your IHD. It's the rounding that's showing the difference between 2.0 and 2.1. What makes it worse is that if you're account is like mine, when you log in and look at your meter readings they are rounded up to the nearest m3 as far as I can see, so there's not even 1 decimal place let alone the 3 that they are receiving AND using.

    I think the lack of decimal places shown in the conversion to kWh also explains the difference, see the note against '40.1' - "Average calorific value shown to one decimal place", this suggests they use a value to more decimal places.

    I can imagine that someone at eon-next has thought that customers will find meter readings on their bill to 3 decimal places far too confusing. In reality those who would find it confusing probably don't even look at it but those of us that do look and check just see mathematical errors because of their lack of detail.

    Why take meter readings to 3 decimal places, show the same readings rounded to 0 decimal places on our accounts and then print a bill to 1 decimal place?
    There's nothing like consistency and attention to detail, or not!
  • meldrewreborn's Avatar
    Level 91
    @Andy65

    I’ve a gas meter that is imperial. An approximate conversion to kWh is to multiply the reading by 31. So one unit on the reading means 31 kWh which at current prices, soon to double, comes to £2.30 approximately. I think the small fractions add up to make big differences to Eon.
    Current Eon Next customer, ex EDF, Zog and Symbio. Don't think dual fuel saves money and don't like smart meters. Chronologically Gifted. If I offend let me know by private message, but I’ll continue to express my opinions nonetheless.
  • JimL's Avatar
    Level 5
    @Andy65 Andy - Only Eon-Next use decimal places (1) in my experience. Even Eon-notNext rounded down to whole numbers. And if I submit meter readings, there's no room for a decimal place so a reading of 769.9 would be entered as 769.
    The issue here is the next bill will show "previous reading" 769.9 "New reading" 775.6 (or whatever it will be) and consumption of 5.7 Kwh (if they get it right).
    That will still leave the 'overhang' of 0.1 from the previous bill. Whether they use decimal places or not, it's a simple arithmetic error and an overcharge.
  • JoeSoap's Avatar
    Level 91
    @JimL

    I've had a look at a few recent statements as you suggested and of the ones I looked at the actual monthly unit consumption calculations are accurate.

    When looking at the calculations for converting units into kWh I looked at my last two statements and there are discrepancies...

    By my calculations, using my new gas rate of 12.87p/kWh, I worked out I would have been overcharged by approx. 3.8p on one and undercharged by approx. 2p on another so the average error is less than 1p per month, just looking at two statements. If I used the actual price per kWh using the old rates at the time of the statements then the monetary error would have been miniscule.

    It may be it all works out as close as makes no difference in the end although I wouldn't know. In principle you are making a valid point, but for me, with a required monthly payment of over £500, I decided not to look back further if we're only talking about 10p per year... and for all I know, it may end up 10p in my favour. Mind you, I doubt it.
  • Andy65's Avatar
    Level 46
    @Andy65 Andy - Only Eon-Next use decimal places (1) in my experience. Even Eon-notNext rounded down to whole numbers. And if I submit meter readings, there's no room for a decimal place so a reading of 769.9 would be entered as 769.
    The issue here is the next bill will show "previous reading" 769.9 "New reading" 775.6 (or whatever it will be) and consumption of 5.7 Kwh (if they get it right).
    That will still leave the 'overhang' of 0.1 from the previous bill. Whether they use decimal places or not, it's a simple arithmetic error and an overcharge.

    Meter reads have historically always been rounded down, or rather you ignore the decimals, as far as I know. That was with conventional meters, I've recently had smart meters fitted so I have idea what other suppliers show on bills with smart meters.
    All I'm saying is that it looks like smart meters are sending the read to 3 decimal places and on your bill they are rounding that to 1 decimal place.

    If you are seeing 0.1m3 error, and my last bill shows the same as well, it's possible that it could easily be 0.051m3 that's been rounded up. Either way, there's no disputing the whole numbers and the rounding up/down will average out.
    If eon-next were to show the 3 decimal places for each read on the bill and the numbers don't add up, then that's a different thing.

    The 3 decimal places could be .099 = .1 on your bill, or .051 = .1, equally .049 could be .0 on your bill.

    Whilst the way they're showing it on the bill amounts to nothing more than stupidity to be honest, I think that your over thinking it with regards to being overcharged, unless I'm missing something.
  • Andy65's Avatar
    Level 46
    @Andy65

    I’ve a gas meter that is imperial. An approximate conversion to kWh is to multiply the reading by 31. So one unit on the reading means 31 kWh which at current prices, soon to double, comes to £2.30 approximately. I think the small fractions add up to make big differences to Eon.

    On the bill eon-next make a point of saying "Average calorific value shown to one decimal place". That suggests that they are showing it to one decimal place but may be using a more accurate number in the actual calculation.

    My Mum has an imperial meter and there is a slight difference in the conversion to kWh on the bill compared to when I work it out. However, the bill shows 'the average calorific value to one decimal place' to be 39.4, if it was actually 39.42 then it's pretty much spot on.

    As I've said, eon-next aren't doing anyone any favours by not showing the full values used, whether that's meter reads and/or the calorific fudge factor.
  • Andy65's Avatar
    Level 46
    Thanks @theunknowntech for that, I won't pile in straight away but I'll keep it in reserve just in case my insomnia comes back 😉.
  • Mac9091's Avatar
    Level 5
    You say it may only be pennies but they all add up.

    Just think if eon "mistakenly" took an extra penny from every customer in every direct debit...that's a lot of free money at the end of the year.

    And how many people would complain about a few pence, let alone even notice it?