Aussie Home Gas Information
A common question asked by our clients is, how much energy is there in an LPG gas bottle, when compared to electricity. Here are some simple facts about lpg gas versus electricity:
- 1 kg of LPG gas contains 50.4 MJ [Mega Joules] of energy.
- 1 kWh of electricity = 3.6 MJ of LPG gas.
- One 45 kg LPG gas bottle [45 kg x 50.4 MJ = 2268 MJ of energy.
- Other bottle sizes are: 9 kg = 453. 6 MJ : 2 x 45 kg bottles = 4536 MJ
Other useful information:
- Green House Gas [CHG] Emissions 3.6 MJ Gas = 0.2 kg CHG
- CHG for coal fired electricity = 1.4 kg CHG
- 1000 Mega Joules = 1 Giga Joule
- 1 x 45 kg bottle = 630 kWh
How Long Does A 45 kg Bottle Of LPG Last?
Firstly you will need to know how much gas your appliance uses in MJs per hour. This may be stated on the appliance's energy label, if not it should be stated in the specification section of the instruction manual. The 'appliance plate' should also state the required information.
The following example uses a heater with 12.6 MJ consumption of gas per hour. The consumption figure assumes it is on full or high. This does not take into account any thermostatic control, which will always be a saving or work out to be additional hours of operation.
Divide the energy within a 45 kg bottle 2268 / 12.6 MJ/h = 180 hours.
Where the heater is operated for 3 hours per day, the gas would last for approximately 2 months.
180 hours / 3 hours per day = 60 days : 2 months
 How Many Bottles Will I Need A Year?
For this example we will use a gas water heater. The label clearly suggests a yearly gas consumption of 22,200 MJ per year.
This is divided by 365 resulting in an average daily use of 61 MJ per day.
The number of LPG bottles required per year can be easily worked out by dividing the suggested annual gas consumption by the amount of gas a bottle contains.
22,200 / 2268 = 9.78 bottles : 10 bottles per year.
What we are not told by this label is the number of MJs this appliance uses on an hourly basis.
What's The Cost Of A 45kg LPG Gas Bottle?
This can vary quite a lot in price, as delivery costs can really hike the total cost! The price we pay for bottled LPG gas currently [October 2011], is $130 delivered. There is a bottle rental of $30 per year, per bottle.
You may get a better deal by bundling the gas with your ELECTRICITY PROVIDER. This is not the case always, so it pays to shop around.
Flueless / Unflued Gas Heaters
We are often asked questions on whether flueless / unflued gas heaters are healthy or unhealthy.
Are You Aware You Need Adequate Cold Air Ventilation When Operating These Heaters?
In most manufacturer's documentation it states adequate ventilation is a requirement! How much ventilation though and what type on a cold night, results in most homes we have visited having NO VENTILATION!
Read our blog entry FLUELESS HOME GAS HEATERS & WINDOW VENTILATION. More information on unflued gas heater residential regulation, can be found on our LINKS page.
In layman's terms this means:
Every 10 metres of floor area needs an OPEN window of 0.6 x 0.9 metres!
Now on a cold night, none of our clients when asked were going to do that! So we know the required ventilation is not being applied in most homes!
So How Big Is Your Room & What Is The Open Window Requirement?
The required ventilation is 5% of the floor area. Use the table below to give you an idea of a comparable window size that you should have open, to supply the ventilation.
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