How do British Gas Calculate Gas Use/Cost

peopleiknow1

I was switched from Peoples Energy in Sept 21 when it ceased trading.

since the switch, I’ve been unable to get any useful info from my online account, nor received a single bill.

in the end I submitted a complaint via the website; 2 weeks later they finally contacted me.  After some back & forth with me saying I would complain to Ofcom they agreed to send me a bill.   

A bill for just over £2K arrived the day after, (£1.5K Gas, £500 Electric….normally my Electric use is always higher than Gas, so was surprised.  

No where on the bill does it show how the Gas Charge is calculated, so on to goggle I went, eventually finding a pdf from British Gas on how to work out your gas bill.  

Following their instructions I get the cost to just short £500, £1K less than their calculations.

I expected our costs would have increased as a result of the switch, but to double; £2k is a years worth of energy costs prior to the collapse of Energy Companies in Sept 21.

So, Just wondering if anybody else as been over charge by British Gas?

QrizB

Usually, where there's a disagreement over gas bills it's because one party thinks the meter is metric and measuring cubic metres and the other thinks it's imperial and measuring (hundreds of) cubic feet.

The difference between the two is a factor of 2.83, which is roughly the difference between £500 and £1500.

Look at your gas meter. Does it say m3 on the front of it, or ft3?

peopleiknow1

I've checked my last bill with People's Energy and they use the following formula:

Usage (in M3) X Calorific Value (39.8) X Volume Correction (1.02264) / 3.6 = kWh - According to BG website they use the same formula.

Using Excel I put this data into a spread and I can recreate my People's Energy bill spot on the the penny, however when I try to recreate my BG bill I get £475.76, whereas BG get £1363.06. 

The bill from BG doesn't show how they calculate my costs, could they now be using a different formula and not have updated their website? 

BUFF

honestly, this is so close to what QuizB raised that I would check it first.

pochase

How many units gas have you used? What does BG claim that is in KWh?

Is the formula on your bill, or did you only get it from the web site? If BG "believes" you don't have a m3 meter it would explain why they have three times the cost. We have seen it here before that a wrong meter type is used after the transfer.

There is not just one formula, there is one formula for meters in m3, and one for meters in ft3, the ft3 one will be the 2.83 times the KWh per unit as the m3 one. 

Comparing the two amounts their calculations is 2.87 higher than yours, so most likely they believe you have a ft3  meter.

peopleiknow1

There is no formula on the BG bill showing how the have calculated costs, I used the one shown on my last People's Energy bill, and found a section on BG website confirming the use the same formula..

Units used = 1093

BG are showing 35195.12 kWh on my bill.

Gerry1

BG have assumed that you have an Imperial meter (ft3).  They will have included a multiplier of 2.83 to convert your reading (hundreds of cubic feet) into cubic metres (m3).

If in reality you have a metric (m3) meter your consumption will be 2.83 times the correct value.  Take a look.

peopleiknow1

I will check my meter when I get home tonight. 

Am I right to assume that imperial would be used on older meters, and metric on new meters....if so, then it if definitely a metric meter as I had a new meter fitted around 4-5 years ago? 

Gerry1

Yes, Imperial meters were the norm but replacements became metric.  Sounds like you'll be due a refund.

pochase

Yes, definitely they are assuming an imperial meter. Strangely we have seen a few threads where the old supplier would use the m3 calculations, but report an imperial meter to the new supplier. Will be a bit of fun to get it through to their support people. Best take a photo that shows the m3 on the meter and get it to them.

Your calculations will never be spot on . There will be always a small difference between you calculations and the calculation of the supplier as you don't know Calorific Value (39.8) from the formula. The value changes all the time regularly, but the difference are quite small. The value can be between 37.5 and 43, so that explains why the difference between your and their calculation is not exactly the 2.83

Gerry1

If dozy Ofgem were any good they would mandate that gas bills must clearly state whether the meter is believed to be Imperial or metric, to show and explain the formula used to convert the volume to kWh, and to advise the consumer how to check that their meter's classification is correct.