How Long Does a 45kg Gas Bottle Last
“How long does a 45kg gas bottle last?” is one of the most common questions we hear.
It all depends on the total of the gas consumption ratings of the gas appliances, as expressed in MJ or MJ/hour.
It all just takes some basic arithmetic.
There is no single answer to this question and a bit of explanation is required to get to the answer for your specific situation.
Figuring it out is actually easy.
But first, some background facts…
What is a 45 kg Gas Bottle?
A 45 kg gas bottle is the most popular size of gas bottle in Australia, as it can be used for home LPG gas bottle exchange and automatic LPG gas tanker delivery to both home and business customers.
It it is large enough to last yet still transportable to users.
45kg Gas Bottles as Home Gas Bottles
The 45kg gas bottles are, by far, the most popular size for home gas bottles.
It is the ubiquitous gas bottle seen in pairs on the sides of homes and businesses.
They come with POL valves.
45 kg Gas Bottle Price
You can access the 45 kg gas bottle price through the 45kg pricing page.
How Many Litres in a 45kg Gas Bottle
There are 88 litres of LPG gas in a 45 kg gas bottle based on propane at 1 kg = 1.96 L.
How Many MJ in 45kg Gas Bottles?
There are 2205 MJ (megajoules) in 45kg gas bottles based on propane at 1 kg = 49 MJ.
45 kg Gas Bottle Dimensions
A 45 kg gas bottle dimensions are approximately 375mm in diameter, 1250mm in height and a nominal 88L capacity.
An empty 45 kg gas bottle weighs approximately 33kg. When full, a 45 kg gas bottle weighs approximately 78kg.
How Long does a 45kg Gas Bottle Lasts
Here are some typical examples of how long a 45kg gas bottle lasts:
- A 45kg gas bottle lasts 52 days based on 16 L/min Hot Water used for 20 minutes per day
- A 45 kg gas bottle lasts 244 days based on 9 MJ Cooktop Burner used for 60 minutes per day
- A 45kg gas bottle lasts 49 days based on 15 MJ Gas Heater used for 3 hours per day
- A 45 kg gas bottle lasts 44 days based on 25 MJ Gas Fireplace used for 2 hours per day
These estimates are based on running at maximum setting/rate.
Duration would be longer on lower settings.
Calculations Based on MJ/hour or BTU/hour
How long an LPG gas bottle lasts depends on the appliances used.
Gas appliances energy consumption is rated in MJ/hr or BTU/hr.
Gas bottle energy content is expressed in MJ or BTU.
By dividing the MJ consumption into the gas bottle MJ content, you get the number of hours that the gas bottle will last.
The same is true for BTUs.
Add 4.4% to the estimates provided for a 47kg gas bottle.
Here are some estimates on how long a 45kg gas bottle will last:
| How Long does a 45kg Gas Bottle Last? | |||
| Gas Heater | 2 hrs/day | 3 hrs/day | 4 hrs/day |
| • 15 MJ Heater | 73 days | 49 days | 37 days |
| • 25 MJ Heater | 44 days | 29 days | 22 days |
| Gas Hot Water | 10 min/day | 20 min/day | 30 min/day |
| • 16L/Min 124 MJ | 105 days | 52 days | 35 days |
| • 26L/Min 199 MJ | 66 days | 33 days | 22 days |
| Gas Cooktop | 30 min/day | 60 min/day | 90 min/day |
| • 9 MJ Burner | 489 days | 244 days | 163 days |
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• Durations shown assumes that you use the appliance on the maximum setting.
• Gas consumption would be less, and the duration longer, on lower settings.
• Numbers have been rounded and are only estimates.
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Read more to learn exactly how to calculate for your home…
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Important Reference Information
Here are some reference numbers you will need to know:
Energy equivalent conversion:
1kW/hour = 3.6MJ
1kg of LPG = 1.96 litres of LPG (propane)
LPG – propane – contains approximately 25MJ per litre
How to Use Less Gas at Home – Efficiency Matters
How to use less gas at home is all about the appliance efficiency ratings.
MJ inputs and kW outputs are directly related but are affected by the efficiency of the appliance.
For example, a 25MJ heater with a 5.8 Star energy rating has an output of 6.2kW.
Now, if you do the maths, dividing 25MJ ÷ 3.6MJ, you would expect that the output to be 6.94kW, not 6.2kW.
The difference is that, at 5.8 Stars, the heater is 89.3% efficient.
No gas appliance is 100% efficient, which is why we have the Star rating system to judge the relative performance of different models.
45kg Gas Bottles with Gas Heater Consumption Calculations:
The following calculation applies to 45kg gas bottles powering a 15MJ gas heater.
A 15MJ 5.8 Star gas heater running at its maximum setting will last approximately 147 hours.
We know this because the gas bottle contains 2200MJ.
The math is as follows: 2200MJ ÷ 15MJ = 147 hours.
However, this same heater, when set on low, consumes 6.0MJ.
So, if you operate it on low only, it will last 367 hours (2200MJ ÷ 6MJ = 367 hours).
As most people would vary the settings, depending on the temperature, the gas bottle will last some duration between 147 and 367 hours.
So, if you use your heater for four hours every evening, you would expect your gas bottle to last anywhere from 37 to 92 days.
45kg Gas Bottles with Gas Hot Water Consumption Calculations:
The following calculation applies to a 45kg gas bottles powering a 130MJ gas hot water heater.
A 16L/min 130MJ 5.0 Star continuous flow hot water heater running at full capacity will last for 16.9 hours of actual run time.
This equates to about 204 five minute showers.
However, the water heater can run at a flow rate of as little as 3.5L/min.
When running slower, the unit will self-modulate and consume less gas.
This would increase the run time by roughly 4X or to about 68 hours.
This equates to around 816 five minute showers.
Assuming you use hot water for other things, as well, totaling 20 minutes per day at maximum, your gas bottle would last about 50 days.
45kg Gas Bottles with Gas Cooktop Consumption Calculations:
The following calculation applies to a 45kg gas bottles powering a 9MJ gas cooktop burner.
Cooktop burners are an even greater challenge to calculate.
The burners on a particular cooktop could vary from 5MJ for the smallest burner to 9MJ for a medium burner, 12MJ for a large burner and 15MJ for a wok burner.
Add to this the fact that each can be run at less than maximum and you can see the math challenge.
If you use the medium 9MJ burner as the average, you get 244 hours of cook time.
Not surprisingly, many cooking customers report that a single bottle can last more than a year.
Gas Consumption Calculations if You have Multiple Gas Appliances
Now the math gets really challenging!
You really can’t add the MJ ratings of all of the appliances together, as they would rarely be used all at the same time and for the same duration.
The easiest method of calculating would be to estimate how long you would use each appliance per day and total their daily consumption.
Using the previous appliance examples:
- If you use your hot water for 20 minutes per day on maximum. This equals 43MJ of consumption.
- When you use your heater, on maximum, for 4 hours every evening. This equals 60MJ of consumption.
- You cook, using one medium 9MJ burner, on maximum, for 45 minutes per day. This equals 7MJ of consumption.
- Adding these all together, you are using 110MJ per day. Based on this, you would expect a 45kg gas bottle to last for approximately 20 days. (2200MJ ÷ 110MJ = 20)
45 kg Gas Bottle Consumption Calculator Chart
For those who can’t be bothered with the math, here is a quick reference chart with 45 kg gas bottle examples:
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