Gas & electric meters

[Broadback]

I have the old and new meter readings for both my gas and electric, but no bills. How do I convert the meter readings to the units that the suppliers use to calculate bills please?

[Set Square]

The Elecricity meter readings will be in 'units' - i.e. kW.Hrs - and this is simply multiplied by the price per unit, and then any standing charge is added. The suppliers usually use unit prices before VAT, so VAT at 5% has to be added to the total.

Gas is much more complicated, because gas meters measure *volume* of gas used (cubic feet or cubic metres) but gas is billed in kW.Hr units to make it comparable with electricity. The volume therefore has to be multipled by various conversion factors - one (calorific value) of which is variable - in order to arrive at kW.Hrs. Once it's in kW.Hrs, the rest of the process is similar to that for electricity - albeit with lower unit prices.

[Broadback]

Thanks SS, problem with the gas then, there is no way it seems to compare my present supplier with an other.

[Brian G]

Broadback

If you have a spreadsheet application loaded onto your computer you can use the following to calculate your gas usage (or use a calculator)

To convert units to kilowatt hours:

Gas units used x imperial to metric conversion factor [2.8] truncated to one decimal place x volume conversion factor [1.022640] x calorific value [39.9] divided by kilowatt hour factor [3.6] = kilowatt hours used.

This is taken from the back of a British Gas gas bill would you believe? What I did was simply to use Excel in Office 97 Pro to carry out the calculation.

Brian G

[gastec]

NEVER DO CONVERSIONS BY YOURSELF EVEN ALTHOUGH YOU ARE GREAT A MATHS....only supply the exact number index as it is displayed on you meters...its up to the gas and electricity suppliers to do th conversions from imperial to metric...OFGAS the gas regulator set dow a ruling that all imperial gas meter are to be changed by a certai date.....as a rule of thumb gas meters are changed at half ther expected lifespan....so after 15 years expect your meters to b upgrade

-- gastec

[Set Square]

But bear in mind that the calorific value can vary from bill to bill. I don't know what the range is, but I have seen values as low as 38.9

Also, the imperial to metric factor shown on my bills is 2.83 (not 2.8).

[Bob Eager]

But beware - newer meters use cubic metres for 'units', so you then leave out the 'multiply by 2.8' step. Check the meter... Also note that there are slight variations in calorific value and volume conversion factors, but these are probably negligible.

[Set Square]

What the B___ H___ are you on about? How exactly will doing one's own calculation hasten the end of the world?

[Bob Eager]

He never said he was going to do that! Don't be silly.

(but then, you're a diybanter reader...stupidity should be expected)

[Broadback]

Thanks all, I reckon that the info given is accurate enough to judge the cheapest supplier. At the moment I am on this fixed rate, no meter readings supplied. As they are now rapidly increasing their charges I think it is time to make certain they are still the cheapest.

[Broadback]

I hope it is not too late to ask this. To convert from cu ft to metric multiply by 2.83? I am confused, should that be divide by 2.93?

[Set Square]

It *is* multiply - because the cu ft reading is actually *hundreds* of cubic feet - and 100 cubic feet is 2.83 cubic metres.

[Broadback]

Thanks for that SQ Cheers

[Brian G]

Oops, you are correct. Damn varifocal glass again LOL

Brian G

[Brian G]

Pardon?

British Gas actually give the info on how to check gas usage on their bills - and take it from me, when they estimate my bill and I check and query it, the new bill is ALWAYS the same as I calculated.

Brian G