gas meter may record your gas consumption in hundreds of cubic feet, but your
energy company is required to bill you in terms of kilowatt hours (kWh).
So how do we convert hundreds of cubic feet of gas to kilowatt-hours?
For this example take the current reading of your gas meter and deduct the previous
meter reading from it. If your previous figure was an estimate this previously
estimated reading may actually be higher than todays reading, in which case deduct
the previous reading from the current reading. This does not affect the arithmetic
it just means you either have more to pay, OR your energy company owes you something
back because you paid too much before.
Either way the difference between the
numbers is net hundreds cubic feet of gas.
Take this result and multiply it
by 2.83, to convert hundreds of cubic feet to cubic metres.
Multiply this result by a correction factor of 1.022640 and
then by the calorific value shown on your last gas bill. Finally
divide the result by 3.6 to give kWh.
As a very rough check a hundred cubic
foot of gas is beween 28 and 31 kWh depending upon the conversion factors which
the cheapest UK Energy supplier
energy consumers have the option of comparing prices and switching energy suppliers.
Your supplier may be giving you their cheapest deal, but other suppliers may want
your business and may offer you an even better deal to get it. That is what a
competitive energy market is all about.
Cubic Feet to Cubic Metres
A Cubic foot is (12 X 12 X 12)
1728 cubic inches, therefore a hundred cubic feet equal 172,800 cubic inches.
Metre is 39.375 inches, therefore, a cubic metre is (39.375 X 39.375 X 39.375)
61046.629 cubic inches.
Divide 172,800 by 61,046.629 and you get 2.83 to three
Correction factor- Natural mains gas expands
and contracts depending on its temperature and the pressure it is subjected to.
So the amount of energy contained in a cubic meter of gas is worked out using
a standard temperature of 15o C and a pressure of 1013.25 millibars. However,
the temperature and pressure at a British meter is, on average, slightly different.
To correct the figures for the difference, they have to be multiplied by 1.02264.
What is the calorific value of gas, where does
that come into it! and why does it vary?
The calorific value is a measure
of the heat contained in the gas, it represents how quickly the gas can heat up
water to a formula which is applied to the gas when it is tested periodically
at various points throughout the national grid system. In simple terms gas delivered
to homes near the point where it comes ashore contains a different level of moisture
than the gas which is used say 50 miles from the shore.
Moisture in the gas
affects it's performance and so the calorific value element should ensure that
a hundred cubic feet of gas used inland, costs
the same to the consumer as
a hundred cubic feet of gas consumed on the coast - for doing the same amount