Conversion factor on gas bill

[Rumpelstilz]

On the gas bill the energy used is calculated as Units x Conversion factor. I suppose the Conversion factor is related to the pressure as Energy = Volume x pressure. How is this C. factor determined and, as it changes all the time, how can the gas supplier set a value for a period of two months?

 

[Towger]

From Board Gáis's revamped (and not for the better Highspeed Internet and computer required!) website

What is the conversion factor?
The meter in your property measures your gas usage in cubic meters or cubic feet depending on the meter that is installed. As the unit rate charge on your bill is based on kWh, we need to convert the cubic metres or feet into kWh's. This is done by way of a conversion factor. This conversion factor measures the heat content of the gas. The reason for this is that gas comes from different sources e.g. Kinsale or is imported and would be of varying heat content.