Elgas LPG Gas Blog

How Much Gas is Left in the Gas Bottle?

Including "How To" Video

Checking the level of remaining gas, in a gas bottle, is an easy process.

To make sense, it helps to also explain how LPG works

Measure the Amount of LPG Gas Remaining in a Cylinder

How to Check Gas Bottle Level

The short version:

Pouring a jug of hot water down the side of the cylinder1. Use a jug of hot tap water from your home - More is better.

2. SLOWLY pour the hot water down one side of the gas bottle.

Be careful not to scald yourself!

3. A line of condensation may appear, indicating the gas level.  If not:

4. Wait a few seconds and then run your hand down the same side of the gas bottle, where you poured the water.

5. You should feel a change of temperature at the level of the gas.

6. If you feel no difference, the gas bottle may well be empty.

Read more on why this works and for tips & tricks to make it even easier…

Did You Know that Your LPG Boils?

LPG is stored under pressure, as a liquid, in a gas bottle.  
It turns back into a gas by 'boiling' into gas vapour.  
This happens at the very low temperature of -42°C. 
To boil, the liquid LPG draws heat from the steel walls of the gas bottle. 
This, in turn, makes the gas bottle feel colder than the ambient temperature.

At the Same Time You Can Get Ice on Your Gas Bottle

Ice on LPG gas cylinderThe gas bottle gets even colder when you are actually using the gas. 
Under the right conditions, when you are using gas very rapidly, ice can even form on the gas bottle!

Pressure Gauges Don't Work for LPG

With compressed gas bottles, like scuba tanks, pressure drops as the compressed gas is used, so a pressure gauge will indicate the remaining gas level.

However, LPG is not compressed gas, it is liquefied gas. 

The vapour pressure varies with temperature but not with the level of gas in the bottle.

As LPG is a liquefied gas, the vapour pressure inside the cylinder will remain the same from full until the last of the liquid LPG is vapourised.

So, if your are trying to determine the level of LPG remaining, pressure gauges don't work.

LPG Cylinder Level Indicator

So, we use this as our LPG cylinder level indicator.
How?  Well, we pour hot water down the side of the gas bottle to heat the steel. 
The steel above the level of the gas will retain the heat longer than the steel below the level of the gas. 
This makes it feel warmer above and cooler below the gas level.  
The point at which you feel the temperature change is the level of the gas inside the bottle.

How to Measure the Amount of LPG Gas Remaining in a Tank?

How can I tell if a home heating propane tank is empty, without the gauge?

This test works with either 45kg home gas bottles or BBQ gas bottles:

Checking gas bottle with hot water1.    Do NOT use boiling water, as you would risk scalding yourself. 

Water from the hot water tap of your home should work fine.

2.    Using care, SLOWLY pour the hot water down one side of the gas bottle. 


More water is better, as it will make it easier to feel the difference in temperature.

I actually fill a cleaning bucket with hot tap water when I check mine. 

3.  A line of condensation may appear, indicating the gas level.  If not:

4.  Wait a few seconds and then run your hand down the same side of the gas bottle, where you poured the water.

5.  You should feel a change of temperature at the level of the gas. 

If you feel no difference, the gas bottle may well be empty.

The following short video (0:48) shows how to tell how much gas is left...

Quick Tip Number 2:

The test works even better during or after you use one of your LPG appliances.

For example, if you have LPG hot water, do the test right after someone takes a shower.

How Full is Full?

Also, please remember that gas bottles are designed to be full at 80% or just over 3/4.

This allows for the natural expansion of the gas during warmer temperatures.

For safety reasons, NEVER open the valve on an unattached gas bottle to check for remaining gas, even if you think it is empty.

 Alternative Way to Check

An alternative way to check a BBQ size gas bottle is by using a scale. 

Disconnect the bottle and place it on a scale, making sure the valve is firmly closed.

The tare (empty) weight of the bottle is stamped on the neck ring.

The difference between the scale reading and the tare weight should indicate approximately how much gas remains in the bottle.

8 Tips for Never Running Out of LPG Gas Again!

We know that there is nothing more inconvenient than being out of home LPG gas. 
Here are a few handy tips, if you are a gas bottle exchange customer, to help you avoid running out:

1.  Always order gas as soon as the first bottle runs out. 

Don't wait until the gas bottles are both empty or near empty. 

Follow this advice and you are virtually assured to never run out of gas.

2.  Remember to order sooner, rather than later, during the busy winter season.

3.  Remember to check your gas bottles more often in cold weather, especially if you use a gas heater or gas log fire. 

Even your water heater has to work harder in cold weather, as the incoming water is colder.

4.  Having additional house guests can also increase your usage if you have gas hot water. 

Remember to check more often so both you and your guests avoid cold showers!

5.  If you only have one gas bottle attached to your home, you may wish to consider adding a second gas bottle. 

Unless you are on automatic tanker delivery, you will either run out or have to call for a gas bottle exchange before using up all of your gas. 

These are both situations you would surely like to avoid. 

A second bottle solves the problem and is particularly wise if you use your gas for hot water and/or heating.

6.  If you are an Elgas customer, make sure we have your Mobile Number so you receive Gas Check Alerts by Text (SMS). 

These are sent automatically, by our computer, based on your past gas usage. 

With Gas Check Alerts, you will never forget to check your gas bottles again.

7.  Remember to increase how often you check your gas bottles if you install additional gas appliances.

8.  Also, be certain to tell your supplier if you install additional appliances, especially if you are on automatic tanker delivery, so we can adjust your delivery schedule.

Follow these tips and you should enjoy using of your gas appliances without interruption.



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The information in this article is derived from various sources and is believed to be correct at the time of publication. However, the information may not be error free and may not be applicable in all circumstances.