[mvhvv]

I'm not sure if things are different outside Australia, but it's probably been 15-20 years since I've lived in a house with a hot-water storage tank. As far as I know most places seem to have instant/continuous systems that heat the water on demand as it passes through the line.

Solar-heating definitely makes storage make more sense, but I don't know how the numbers actually work out on that one.

[frosted-flakes]

Or for heat pump water heaters, which have unbeatable efficiency. Still not cost-effective in many areas compared to gas-burning heaters, but they use much less energy.