Gas hot water heaters come in different types, Instant and Storage cylinder.
Gas hot water heaters are quite popular especially in the new home builder market and with smaller land sizes not being able to accommodate a 650mm wide hot water tank down the side path.
Instantaneous Natural Gas and LPG gas hot water heaters are not much larger than a small suitcase which is mounted on a wall, the tankless instant heating hot water heaters are great room savers, especially with home block sizes getting smaller & smaller. Most of the gas, instant no tank, hot water heaters use an electronic ignition source that requires a power point to ignite the gas, rather than a constant pilot light burning gas away 24 hours a day, which makes them a great gas saver until there is a black out, then you’re having cold showers as there’s no reserve water heated.
LPG gas has become quite expensive to purchase with handling and labour costs to have it delivered to your home on top of the gas itself and you also have to pay rental each year for each gas tank you have makes it more expensive to run your hot water heater than a off peak electrical water heater and you will need 2 x 45kg gas bottles.
Some newish developments and community planned suburbs that didn’t have access to natural gas had gas mains run from a large main LPG gas cylinder that is metered so you don’t have the bottle rental when gas connected to your home, this infrastructure was generally supplied by a gas supplier so you only have them to use as your gas provider.
In the city and surrounding suburbs that have natural gas mains have gas supplied at a rate that is 25-45% cheaper than the bottles but now the gas providers are changing a service fees with the gas, I have heard cases of cases where this is being over $50 added per quarterly gas bill on top of the metered gas that is used.
Unlike using gas for cooking or your barbecue, that use little gas and have small burners, heating water is very different and the volume of gas needed is quite large