Gas Water Heating
Gas water heating in New Zealand is usually done by instant gas systems. This is where no water cylinder is in the house. The big advantage is that the vast majority of water heated is the one used. Only what is left in the pipe after usage of hot water is wasted (whereas in a hot water cylinder all water in the cylinder is heated). Another, less common version is to have a hot water tank that is heated via gas.
Types of gas:
There are several different types of gas that can be used. However, we found only some options that are from renewable resources: bio-methane (made from biogas), ethanol (made from alcohol), bio propane (bio- LPG). In our view these are the only gases that should be considered. Mining of gas is sometimes done with fracking, which requires a lot of water. The dumped wastewater contains harmful toxins. On top of that, fracking could cause small earthquakes (1).
Advantages of gas water:
Instant gas does not require a water cylinder
No shortage of hot water as long as you have gas (family of 6 or 7 might struggle to all have a hot shower one after the other with a water cylinder system)
Disadvantages of gas water:
You will have to buy fuel
Depending on gas used environmental damages on extraction (1)
(1) Forbes; Consumer Tech; Quora; 'The Environmental and Social Impacts of Natural Gas Fracking'; 17.04.2017