How long does a 45 kg gas bottle last in an Australian home?
There is no single answer. Here is how to estimate how long a 45 kg LPG bottle will last in your home, using your own appliances.
Why there is no single number
How long a 45 kg bottle lasts depends on which appliances use it, how big they are, how often they run and the season. A household that only cooks with gas uses far less than one that also heats water and the house.
A simple way to estimate
LPG holds roughly 49 megajoules (MJ) of energy per kilogram, so a full 45 kg bottle holds roughly 2,200 MJ.
Each gas appliance has a rating in MJ per hour on its compliance plate or in its manual. Multiply each rating by the hours you use it per day, add them up, and divide 2,200 by that daily total to get an approximate number of days.
Example only: if your appliances added up to 50 MJ a day, one bottle would last about 44 days. Your own figure could be much higher or lower.
Why it runs out faster in winter
Hot water systems work harder when incoming water is cold, and space heaters only run in winter. Many households notice bottles emptying noticeably faster from June to August.
Use your own history
The most reliable estimate is your own: note the date each bottle is swapped or refilled. After a few changes you will know your typical summer and winter usage.
Get a warning before it runs out
Many homes have two bottles with a changeover valve, but it is still easy to miss when the second bottle starts running. A WiseTank sensor under a steel bottle shows the remaining percentage in the TANK IOT app and can send a low-level alert, giving you time to order a refill.