Understand your bill
The Common Factor
We use The Common Factor to calculate your gas hot water usage by determining the amount of gas (in mega joules) required to heat a litre of water. It’s calculated by dividing the total amount of gas used to heat the water (MJ) by the total amount of water (L) used as recorded by the central hot water system.
Information for NSW customers only excluding residents of Wagga Wagga and Tamworth
If you live in NSW, you may notice that your usage has been multiplied by 10, as well as The Common Factor - this is because the hot water meter measures your usage in decalitre (a metric unit of capacity equal to 10 litres).
The Common Factor is provided to us by your distributor who is responsible for reading the master meters (these meters are the ones common to the entire apartment block).
To calculate your bill, we multiply your individual usage by 10 to determine your usage in litres, and then by The Common Factor (as The Common Factor is the amount of gas required to heat a litre of water).
Your Meter Reading = 1111 dl (x10)
Your Meter Reading in Litres = 11110
Gas usage of all units = 57544 MJ
Water usage of all units = 126190 litres
Common Factor = 57544 / 126190 = 0.4560107 rounded to 0.456011
Energy (MJ) = 1111 x 10 x 0.456011 = 5066.28 rounded to 5066 MJ