cubic feet Vs. cubic meter please help me to understand!

faramir_2

sorry if this has been posted somewhere in this forum before but I couldn't find it!

I have an imperial meter (cubic feet) and I wanted to see how much 180 cubic feet of gas (as my meter reads) would cost with npower. I visited this site ermmm i am not allowed to post links but you can find it on 'mysmartmeter -- ukpower.co.uk

and found that 180 cubic feet of gas costs almost 3 times more than 180 cubic meter! how is that so? surely 180 cubic meter of gas is much more than 180 cubic feet of gas?! could someone tell me how this is calculated?
many thanks

Cardew

A gas unit is 100 cubic feet which is 2.83 times bigger than a cubic metre.

So 180 gas units in your meter are approx 5,670 kWh around £180?

faramir_2

Cardew wrote: »

A gas unit is 100 cubic feet which is 2.83 times bigger than a cubic metre.

So 180 gas units in your meter are approx 5,670 kWh around £180?

thanks, so every time that central heating is on for 1 hour it uses 100 cubic feet of gas? is that the right amount of gas to heat up a 3 bed house? or is it rather far too much? I use about 6 units a day and that is my central heating is on for a total of 5 hours in total.

molerat

That seems very high, are you sure your meter is imperial ? Yesterday I used 12 metric units (= 4.24 imperial) keeping my 3 bed detatched in N Scotland at 20 deg for 24 hours when outside reached -3 max. You are using 17 metric units in 5 hours :eek:

brewerdave

I looked back to last Winter - in the coldest spell I was only using just over 4 imperial units per day to heat a 5 bedroom detached with the heating on for ~ 18 hours a day.

macman

faramir wrote: »

thanks, so every time that central heating is on for 1 hour it uses 100 cubic feet of gas? is that the right amount of gas to heat up a 3 bed house? or is it rather far too much? I use about 6 units a day and that is my central heating is on for a total of 5 hours in total.

How do you deduce that from the info given (unless you are saying that you have measured the consumption over one hour)?
The consumption will vary according to the boiler and the rate at which the burner is consuming gas-turn it up and it will burn more. There's no fixed rate that says that 1 imperial unit will last one hour.
If you want to asses your average annual consumption then the way to do it is work out your kWh consumption (calculate from your bills or phone your supplier) and then divide by 365 for your daily usage.

Cardew

faramir wrote: »

thanks, so every time that central heating is on for 1 hour it uses 100 cubic feet of gas? is that the right amount of gas to heat up a 3 bed house? or is it rather far too much? I use about 6 units a day and that is my central heating is on for a total of 5 hours in total.

If it uses 100 cubic feet in an hour, that is approx 31kWh(around £1)

It is perfectly possible that initially a boiler could use that amount, but once the house( and Hot water tank?) are up to heat, it shouldn't be using that amount.

macman

I think the OP is confusing a unit of volume (100 cubic foot ) with a unit of energy (1 kWh).

faramir_2

thanks guys. I am using about 6 units (my meter is Imperial) a day to heat up the house and hot water 2/3 showers. I still think that's too much since the boiler for C/H is only on for a total of 5 hours. is it possible the meter is faulty? the meter is about 30 years old and i am in the middle of a dispute with the previous supplier. I paid about £1200 for gas last year (100 per month) and they are demanding another £680! that's nearly £2000 per annum!!! it looks like its going that way this year as well, with the average of 180 units per months: nearly £170 per months since Nov till possibly April/May. do you think the meter is faulty? I think it must be!

Cardew

The older type gas meters are rarely faulty in that they 'run fast' i.e. over-read. They are simply a vane turned by the incoming gas.

Obviously £2,000 a year is about 3 times the average annual usage of 20,500kWh per year(in the region of 60,000kWh) and presumably as your house has 3 beds it is not huge?

That said using 6 gas units a day(approx 180kWh) in this exceptionally cold weather would indicate a consumption of well below 60,000kWh p.a. albeit still far too high.

A very old inefficient boiler would contribute to high consumption, as would poor insulation, but it is difficult to see that causing such high consumption.

If your meter is the old dial type, are you sure you are reading it correctly? It is easy to misread as the pointers run clockwise and anti-clockwise on alternate dials.

faramir_2

Cardew thanks for the info. It is also possible that my boiler - over 10 years old - could be inefficient. Is there any way I can test it's efficiency?
thanks