# How Long Does a 45kg Gas Bottle Last - Chart:

## Here are some estimates on how long a 45kg gas bottle (45 kg LPG cylinder) 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 • 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.

## A 14.2kg cooking gas bottle will last from about 9 days to 81 days, depending upon burner size and amount of use. If you use a small 5MJ burner for 30 minutes per day, the gas bottle will last 81 days. If you use a large 15MJ wok style burner for 90 minutes per day, the gas bottle lasts 9 days.

#### A 14.2kg cooking gas bottle contains about 202MJ of energy. To calculate how long your cooking gas bottle will last, just divide the 202MJ by the burner size. If you use more than one burner, you need to add their MJ ratings together before you divide.

 How Long Will a 14.2kg Gas Bottle Last? Gas Cooktop Total Hours 30 min/day 60 min/day 90 min/day • 5 MJ Burner 40.4 hours 81 days 40 days 27 days • 9 MJ Burner 22.4 hours 45 days 22 days 15 days • 15 MJ Burner 13.5 hours 27 days 13 days 9 days • 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.

## A 13kg cooking gas bottle will last from about 8 days to 74 days, depending upon burner size and amount of use. If you use a small 5MJ burner for 30 minutes per day, the gas bottle will last 74 days. If you use a large 15MJ wok style burner for 90 minutes per day, the gas bottle lasts 8 days.

#### A 13kg cooking gas bottle contains about 185MJ of energy. To calculate how long your cooking gas bottle will last, just divide the 185MJ by the burner size. If you use more than one burner, you need to add their MJ ratings together before you divide.

 How Long Does a 13kg Gas Bottle Last BBQ Gas Cooktop Total Hours 30 min/day 60 min/day 90 min/day • 5 MJ Burner 37 hours 74 days 37 days 25 days • 9 MJ Burner 20.5 hours 41 days 20 days 14 days • 15 MJ Burner 12.4 hours 25 days 12 days 8 days • 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.

## How long a gas bottle lasts for hot water could be anywhere from 22 days to 105 days or longer for a 45kg gas bottle, depending on how much hot water you use. My wife and I have 45kg gas bottles last for more than four months using it for hot water and cooking.

#### On the other hand, a large family with teenagers who take long showers will use gas much quicker.  Here is a table showing the number of days a 45kg gas bottle will last for hot water.

 How Long Does a Gas Bottle Last for Hot Water 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 • Durations shown assumes that you use the hot water on the maximum flow rate • Gas consumption would be less, and the duration longer, on lower settings. • Numbers have been rounded and are only estimates.

## Important Reference Information

To get started, here are some numbers you will need to know for your reference:

## 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.

## LPG Gas Consumption Calculation if You have Multiple 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:

#### Remember to multiply the results by 1.044 (4.4%) for a 47kg propane gas bottle.

You may also wish to see:

## 45kg gas bottle (45 kg LPG cylinder) LPG Gas Consumption Calculation Chart

For those who can't be bothered with the maths, here is a quick LPG gas consumption calculation chart

## A Megajoule or MJ Probably Isn't What You Think

What is a megajoule and why does it matter when I buy a gas heater or hot water heater or other gas appliance?

What size gas heater or hot water system should I buy?

How do I compare gas appliance prices?

Many people think they know but you might be surprised by the real answer.

## A MJ is NOT This...

I recently watched a product video produced by a major Australian retailer.

In it, a “Product Expert” reviews a Rinnai gas heater.

He did a fair job of explaining the features, even if you could get the same information from the Rinnai web site or product brochure.

The problem was that the presenter lost me in the second sentence when he said:  “That’s 13MJ of heat.”

He also makes a similar statement in at least one other video.

To quote the popular Gen Y meme…  EPIC FAIL!

Sorry, but there is nothing worse than an “expert” giving out bad advice.

## Gas Consumption = MJ

Megajoules per Hour (MJ/hr) ratings on appliances actually indicate the gas consumption of the appliance, not the heat output.

It is often expressed as just MJ.

On the other hand, heat output must also take into account the relative energy efficiency ratings of the models being compared.

How is it pronounced?  Say it as if it were spelled "mega jewel" or "mega jewels", not "mega jowl".

## Heat Output = kWh

Kilowatt Hour (kWh) is how gas heater output is measured.  3.6 MJ of input equals 1kWh of output at 100% efficiency.

However, no gas appliance is 100% efficient.

That is why we have Star Ratings, so we can compare relative efficiency between models.

Appliance output is often expressed as just kW.

## Energy Efficiency - Star Ratings

Star ratings were developed to provide consumers with an easy way of comparing the energy efficiency of different models of gas heaters and hot water systems.

All States now require both LPG and Natural Gas heaters to be tested and certified, under AS4553, by independent testing organisations, such as the AGA and SAI Global.

The Star Rating is based on net heater efficiency.

Net heater efficiency is calculated on the basis of a combination of efficiency measures and takes into account all gas and electrical inputs.

It basically compares the amount of raw energy input consumed by the heater in comparison to the heat energy output provided.

This is calculated as a percentage and then translated into the corresponding Star Rating.