Heating value

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I'm interested to know how Heating Value is calculated and applied to my bill. Is there a place I can download (in Excel format) the heating value for my area for the past three years. Also, does this heating value calculation apply to all service providers from the distributor or does the service provider provide their calculation on top of the distributor's calculation?

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More information at AGL - understand your bill 


A simply search of the internet is all you require.


The heating value is used to calculate the amount of mega joules (Mj) in natural gas. The heating value is impacted by the temperature and pressure at different geographical locations.

Your Bill calculations are made using the heating value that is supplied by your local distribution company.

The pressure factor, also provided by your local distribution company, is used to calculate your gas consumption. The pressure and speed of the natural gas delivered to your premises will often vary and is based on environmental factors, such as temperature and the appliance that is consuming the gas.


As to getting that past information you would need to contact your Gas Supplier.


Note that with both Gas and Electricity you have a Retailer (AGL) and a Supplier / Distributor, your Supplier / Distributor is listed on your Bill and is the company your contact for loss of service.


Now your gas meter only reads the volume of Gas that has entered your pipes to know the start reading and the end reading (on your bill)



Then the formulae

  • ( End read - Start read ) x Heating value x Pressure factor = Usage MJ
  • ( 229 - 220 ) x 38.6336 x 1.0272 = 357.15 MJ
If you are trying to keep up to date you will need to do a manual read and use the formulae
  • ( Current read- End read ) x Heating value x Pressure factor = Usage MJ

However that will only give your usage up to the day of your manual read. So to get an estimate of what your reading for the billing period would be:


Daily Usage MJ= Usage MJ  ÷ number of days since last bill


Estimated Usage MJ = Daily Usage MJ x number of days in billing cycle


Number of days since last  bill is  :    Days = now() - end date of last bill (works in all Spread sheets)


Now to answer your other question.


The formulae's to calculate your Gas usage are above so you can create a Spread-Sheet using those.


Remember if you have a tier billing process, then will have to work out the rate based on your tier system.





If this solves your query then please solve it.

If you like my answer please like it.

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Thanks for the response.

Just one more question, Is the Heating Value figure value derived as a daily, weekly or monthly sum? In other words, what is the period of time that determines the final Heating Value figure that will be used to calculate the amount of gas used in a billing period?


BTW, as an AGL customer myself, to which email address can I send a request for the previous heating value data as I mentioned in my initial post?




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To contact AGL the methods are  HERE.


Simply Left click on the HERE and it should take you to the web page.


You should remember though that when you get a reply that unless the person has an XXXX_AGL name that they are a person like me and just are trying to help you.


I don't actually don't have gas on the premises and the only reason I can answer your question is that I used to give IT support to over 55's for one of the councils in SA.


To the best of my knowledge the Heating Value is fairly constant for most localities (in that the value is the same for your area, but may be different for the next town).




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