A natural gas meter measures the amount of gas consumed by all the gas appliances in a premise. The gas used is measured in cubic meters or cubic feet. However, your gas supplier must bill you on the basis of energy used i.e. kilowatt hours (kWhs). For domestic gas usage a conversion formula is used to convert cubic meters or cubic feet into kWhs. This conversion formula has been approved by the Commission for Regulation of Utilities. The conversion formula can vary nationwide. The formula depends on the local temperature, pressure and calorific value of the gas.
Factor used to convert the usage calculated between an opening and closing meter read from cubic meters (if metric meter) to kilowatt hours - components of the factor allow for pressure, temperature, compressibility and Calorific Value (CV).
Calorific Value is a factor used to calculate the energy equivalent of gas usage (The ratio of energy to volume measured in mega joules per cubic meter (MJ/m). Natural Gas is now obtained from multiple sources, so the CV changes on a daily basis and is calculated on the average daily usage over a billing period.
The method of calculating CV rests with Gas Networks Ireland, is in line with best international practice and has been approved by the CRU. CV is the amount of heat released when a mass of fuel (e.g. Natural Gas) is burned.
Please do not hesitate to contact your gas supplier should you require any further assistance regarding this matter.