Conversion of M3 to Kwh (as opposed to Khw!)

QrizB

peter3hg said:

Edit 2: I think it might just be due to rounding of the m3 value.

I think you're right. All the off-looking calculations have one-decimal-place gas volumes, which you'll get from a smart meter but not from an index reading.

My gas bill is based on index readings and my calculation works out correctly.

A rounding discrepancy of 0.1 cubic metres is about 1kWh, which bounds all the examples so far quoted in this thread.

[Deleted User]

QrizB said:

peter3hg said:

Edit 2: I think it might just be due to rounding of the m3 value.

I think you're right. All the off-looking calculations have one-decimal-place gas volumes, which you'll get from a smart meter but not from an index reading.

My gas bill is based on index readings and my calculation works out correctly.

A rounding discrepancy of 0.1 cubic metres is about 1kWh, which bounds all the examples so far quoted in this thread.

Hence the problems appearing to start when people moved from "do not read the red numbers" to automatic readings.

Truncated CV and rounded/truncated volume makes that calculation quite vague.

calorificvalue

[Deleted User] said:

calorificvalue said:

QrizB said:

calorificvalue said:

OCTOPUS have a new method of achieving this.

This seems unlikely. Can you post an excerpt from your bill showing whatever-it-is that you are disputing?

It is NOT unlikely. It is true. Since spring 2022. OMBUDSMAN informed.
example : 4.1 x 1.02264 x 40.2 / 3.6 = 47.2
CHECK IT - It's not is it? 
===================

Can you please stop spamming everywhere - it messes up the board for anyone trying to give other people advice.

As QrizB said - post a picture of the bit of the bill that has the calculation you dispute.  Post what you think the calculation should be.  Maybe then we can help you understand.

All the bills from Feb 2019 to April 2022 balanced with the exception of odd 1p rounding errors.
Since then all bills have been wrong.

OCTOPUS claim the calculation is a secret and will not divulge the method of achieving the end result.
They've tried to claim faulty meter, weather conditions at certain time of year, then using an average cal val, albeit the average they quoted was different to the bill. The whole scenario is nuts. I have a spreadsheet which worked fine until May, now have to change the cv to force the same bill results. I am just trying to raise awareness of what they are up to and get more people to complain, but because the effect is low value, there seems to be no interest. But 3.5 million times a few pence soon adds up.

k_man

calorificvalue said:

[Deleted User] said:

calorificvalue said:

QrizB said:

calorificvalue said:

OCTOPUS have a new method of achieving this.

This seems unlikely. Can you post an excerpt from your bill showing whatever-it-is that you are disputing?

It is NOT unlikely. It is true. Since spring 2022. OMBUDSMAN informed.
example : 4.1 x 1.02264 x 40.2 / 3.6 = 47.2
CHECK IT - It's not is it? 
===================

Can you please stop spamming everywhere - it messes up the board for anyone trying to give other people advice.

As QrizB said - post a picture of the bit of the bill that has the calculation you dispute.  Post what you think the calculation should be.  Maybe then we can help you understand.

All the bills from Feb 2019 to April 2022 balanced with the exception of odd 1p rounding errors.
Since then all bills have been wrong.

OCTOPUS claim the calculation is a secret and will not divulge the method of achieving the end result.
They've tried to claim faulty meter, weather conditions at certain time of year, then using an average cal val, albeit the average they quoted was different to the bill. The whole scenario is nuts. I have a spreadsheet which worked fine until May, now have to change the cv to force the same bill results. I am just trying to raise awareness of what they are up to and get more people to complain, but because the effect is low value, there seems to be no interest. But 3.5 million times a few pence soon adds up.

Are all the bills wrong in Octopus favour? Or simply rounding type errors that balance out.

It's hard to comment further without more details

calorificvalue

[Deleted User] said:

In the absence of any other information, this appears to be the calculation that the OP is disputing:

4.1 x 1.02264 x 40.2 / 3.6 = 47.2

Which, they correctly determine, is mathematically inconsistent.  The strict result of that calculation should be 46.8199 (to 4dp).

However, the 40.2 is only correct to 1dp, and it is unclear whether it is rounded or truncated.  That gives a possible true value of somewhere between 40.15 (resulting in 46.7616kWh) and 40.2999 (resulting in 46.9362kWh).  Still doesn't come to the 47.2 quoted, but would give some indication to the potential range of variation just from the simplification of this single component.

As @peter3hg says, it could be something to do with using a weighted average of the daily numbers - I can't find any clear information about that.

Here is picture of said bill. I get 46.819868

[Deleted User]

calorificvalue said:

Deleted_User said:

In the absence of any other information, this appears to be the calculation that the OP is disputing:

4.1 x 1.02264 x 40.2 / 3.6 = 47.2

Which, they correctly determine, is mathematically inconsistent.  The strict result of that calculation should be 46.8199 (to 4dp).

However, the 40.2 is only correct to 1dp, and it is unclear whether it is rounded or truncated.  That gives a possible true value of somewhere between 40.15 (resulting in 46.7616kWh) and 40.2999 (resulting in 46.9362kWh).  Still doesn't come to the 47.2 quoted, but would give some indication to the potential range of variation just from the simplification of this single component.

As @peter3hg says, it could be something to do with using a weighted average of the daily numbers - I can't find any clear information about that.

Here is picture of said bill. I get 46.819868

What are the two readings that give the 4.1?

And as k_man said, are there previous bills where the calculation comes out the other way?

calorificvalue

[Deleted User] said:

calorificvalue said:

Deleted_User said:

In the absence of any other information, this appears to be the calculation that the OP is disputing:

4.1 x 1.02264 x 40.2 / 3.6 = 47.2

Which, they correctly determine, is mathematically inconsistent.  The strict result of that calculation should be 46.8199 (to 4dp).

However, the 40.2 is only correct to 1dp, and it is unclear whether it is rounded or truncated.  That gives a possible true value of somewhere between 40.15 (resulting in 46.7616kWh) and 40.2999 (resulting in 46.9362kWh).  Still doesn't come to the 47.2 quoted, but would give some indication to the potential range of variation just from the simplification of this single component.

As @peter3hg says, it could be something to do with using a weighted average of the daily numbers - I can't find any clear information about that.

Here is picture of said bill. I get 46.819868

What are the two readings that give the 4.1?

And as k_man said, are there previous bills where the calculation comes out the other way?

pretty straightforward arithmetic : 3998.0 - 3993.9 = 4.1
Having said that the latest bill contains this : 4009.4 - 4003.8 = 5.7 (I get 5.6!)

k_man

calorificvalue said:

[Deleted User] said:

calorificvalue said:

Deleted_User said:

In the absence of any other information, this appears to be the calculation that the OP is disputing:

4.1 x 1.02264 x 40.2 / 3.6 = 47.2

Which, they correctly determine, is mathematically inconsistent.  The strict result of that calculation should be 46.8199 (to 4dp).

However, the 40.2 is only correct to 1dp, and it is unclear whether it is rounded or truncated.  That gives a possible true value of somewhere between 40.15 (resulting in 46.7616kWh) and 40.2999 (resulting in 46.9362kWh).  Still doesn't come to the 47.2 quoted, but would give some indication to the potential range of variation just from the simplification of this single component.

As @peter3hg says, it could be something to do with using a weighted average of the daily numbers - I can't find any clear information about that.

Here is picture of said bill. I get 46.819868

What are the two readings that give the 4.1?

And as k_man said, are there previous bills where the calculation comes out the other way?

pretty straightforward arithmetic : 3998.0 - 3993.9 = 4.1
Having said that the latest bill contains this : 4009.4 - 4003.8 = 5.7 (I get 5.6!)

Which points to this being a result of rounding on the m3 as suggested above.

If so this should balance out.

[Deleted User]

calorificvalue said:

Deleted_User said:

calorificvalue said:

Deleted_User said:

In the absence of any other information, this appears to be the calculation that the OP is disputing:

4.1 x 1.02264 x 40.2 / 3.6 = 47.2

Which, they correctly determine, is mathematically inconsistent.  The strict result of that calculation should be 46.8199 (to 4dp).

However, the 40.2 is only correct to 1dp, and it is unclear whether it is rounded or truncated.  That gives a possible true value of somewhere between 40.15 (resulting in 46.7616kWh) and 40.2999 (resulting in 46.9362kWh).  Still doesn't come to the 47.2 quoted, but would give some indication to the potential range of variation just from the simplification of this single component.

As @peter3hg says, it could be something to do with using a weighted average of the daily numbers - I can't find any clear information about that.

Here is picture of said bill. I get 46.819868

What are the two readings that give the 4.1?

And as k_man said, are there previous bills where the calculation comes out the other way?

pretty straightforward arithmetic : 3998.0 - 3993.9 = 4.1
Having said that the latest bill contains this : 4009.4 - 4003.8 = 5.7 (I get 5.6!)

In the pre-smart-meter world, those two calculations would have resulted in '5' and '6'.  That wouldn't have been a problem, because the next readings would likely have been smaller to compensate.

In the smart meter world, they're just rounded or truncated versions of the actual numbers used.  Just like the CV is a truncation.

Roundings or truncations on each of these can make a noticable difference.

Have you checked that every calculation is 'wrong' in the same direction?  Are the calculations right if you assume truncation and look at what the value could be?

calorificvalue

k_man said:

calorificvalue said:

Deleted_User said:

calorificvalue said:

QrizB said:

calorificvalue said:

OCTOPUS have a new method of achieving this.

This seems unlikely. Can you post an excerpt from your bill showing whatever-it-is that you are disputing?

It is NOT unlikely. It is true. Since spring 2022. OMBUDSMAN informed.
example : 4.1 x 1.02264 x 40.2 / 3.6 = 47.2
CHECK IT - It's not is it? 
===================

Can you please stop spamming everywhere - it messes up the board for anyone trying to give other people advice.

As QrizB said - post a picture of the bit of the bill that has the calculation you dispute.  Post what you think the calculation should be.  Maybe then we can help you understand.

All the bills from Feb 2019 to April 2022 balanced with the exception of odd 1p rounding errors.
Since then all bills have been wrong.

OCTOPUS claim the calculation is a secret and will not divulge the method of achieving the end result.
They've tried to claim faulty meter, weather conditions at certain time of year, then using an average cal val, albeit the average they quoted was different to the bill. The whole scenario is nuts. I have a spreadsheet which worked fine until May, now have to change the cv to force the same bill results. I am just trying to raise awareness of what they are up to and get more people to complain, but because the effect is low value, there seems to be no interest. But 3.5 million times a few pence soon adds up.

Are all the bills wrong in Octopus favour? Or simply rounding type errors that balance out.

It's hard to comment further without more details

Seems mainly in OCTOPUS's favour, but that's not the point. Even if they all favoured me, it's just plain wrong & incomprehensible. They claim to be making the billing easier to understand, but it's not. I could post all the garbage sent by OCTOPUS here, but that seems way over the top.
The point is that no other supplier seems to use this magic maths. All the bills I have asked friends and neighbours for, all calculate correctly. So why do OCTOPUS need to use some secret calculation that no one can fathom out.