If you want a basic estimate of possible savings or don’t have your gas bills handy, select Typical annual use. The default values are the average annual gas consumption for a three bedroom home and a typical gas tariff.
Your energy use probably varies significantly between summer and winter, particularly for heating. So, for a more accurate estimate, pull out your last four gas bills (paper or from your online account) and fill in the usage and tariff figures in the Quarterly billing table.
On your bill, find the total amount of gas used in megajoules, eg 8765 MJ. It might be called ‘gas consumption’ or ‘gas usage’.
Copy the amount of gas used into the ‘MJ’ field for Billing period 1 below.
Then find the $ tariff. It might be called a ‘charge’ or ‘rate’, eg $0.03456 per MJ. You may have more than one tariff, eg ‘peak’ and ‘off peak’.
Enter the tariff for the lowest of the MJ amounts into the ‘per MJ’ field for the same billing period. Repeat for each of your four bills.
Don’t worry about the ‘supply charge’ – the calculator will account for this.