npower gas calculation and seasonal weighting

Jonan_2

Hi,

My latest gas bill from npower charged me for 215 kWh at the higher rate where the billing period was 13/07/10 to 03/10/10 inclusive. Using the seasonal weighting figures I got from a link in another thread (MSE News: Npower to pay £70m in refunds after billing blunder) I calculated that I should only have been charged for 146 kWh at the higher rate.

My calculation is as follows, where the figures in blue are the monthly weighting for each successive month as taken from the aforementioned npower link.

(18/30 x 46) + 46 + 46 + (3/31 x 271) = 146 (rounded to a whole number)

Have I just made a mess of the calculation or have npower got it wrong?

J

Sterling

Your calculations are perfectly correct.

When you take the overcharge up with Npower, they may say they are working to a different “due date” and hence the extra units. I challenged this, as no such date was shown on my bill, and eventually Npower admitted the error.

Edit – I assume your “18/30” is a typo, and should read 19/31, as there are 31 days in July, but 146 is correct

sofa-spud

Jonan wrote: »

Hi,

My latest gas bill from npower charged me for 215 kWh at the higher rate where the billing period was 13/07/10 to 03/10/10 inclusive. Using the seasonal weighting figures I got from a link in another thread (MSE News: Npower to pay £70m in refunds after billing blunder) I calculated that I should only have been charged for 146 kWh at the higher rate.

My calculation is as follows, where the figures in blue are the monthly weighting for each successive month as taken from the aforementioned npower link.

(18/30 x 46) + 46 + 46 + (3/31 x 271) = 146 (rounded to a whole number)

Have I just made a mess of the calculation or have npower got it wrong?

J

Not surprising, seems to be a similar problem to the 'last' error I found with them detailed here...
https://forums.moneysavingexpert.com/discussion/2691611

I make it 145 units(31 days in July), so
((31-13)/31*46)+46+46+(3/31*271) = 144.9KWh's

sofa-spud

Sterling wrote: »

When you take the overcharge up with Npower, they may say they are working to a different “due date” and hence the extra units. I challenged this, as no such date was shown on my bill, and eventually Npower admitted the error.

When I challenged them on their recent error, they didnt try to claim this, but the standard 'Yes its correct'. Until I went though the calculations when they agreed and agreed to refund the overcharge immediately to my account.
I spoke to a Richard Hill at the time, who seemed to be able to follow my maths:T

Sterling

sofa-spud wrote: »

(31-13)/31*46)+46+46+(3/31*271) = 144.9KWh's

As the dates quoted by the OP were said to be inclusive, I worked to (31-12) rather than (31-13), and hence the slight variation in our answers.

Jonan_2

Thanks for the replies, Sterling and sofa-spud. It was my typo to assign 30 days to July. The billing period did start on 13 July as the previous period's closing reading was 12 July, so, yes, the fraction for July should have been 19/31.

I'll take it up with npower after I've scrutinised all the bills I have on file to see if there are other discrepancies. What intrigues me is what algorithm are they actually using for my account and countless others like it?

Thanks again.

J :wave: