You can find how we calculate your gas usage on page 5 of your monthly bill.
To see your latest bill click here.
The calorific value is the amount of energy released when gas is burnt. The quality of gas varies slightly every day so the average calorific value for the statement period is used when calculating the number of kilowatt-hours used.
The correction factor is applied to account for fluctuations in temperature and pressure of gas in the UK. The correction factor is always 1.02264.
Imperial or Metric
If you have an imperial gas meter, we'll first need to convert your usage from imperial (Ft3) to metric (M3). To do this, we multiply the imperial units by 2.83.
This then shows your usage in metric units and we use the following example formula to calculate your gas charges:
Your units= 2 (M3)
Volume Correction *1 x 1.02264
Calorific Value *2 x 39.3
Convert to kWh / 3.6
kWh used= 22
* 1 The change in pressure of gas from sea level to your home
* 2 The amount of energy released when gas is burned