Markets and opportunity. Peas and carrots.
Hand in hand go such things, and one would expect that in our new water conscious world, any device that can reduce water use in the home will go hand in hand with the phrase 'in demand'.
Here’s one device that has the benefit of being automatic and energy free.
It diverts the cold water sitting in the pipe between the hot water system and the hot tap to a storage (toilet, rain tank etc), then diverts the water back to the tap as it warms.
For all those whingers who need hot showers in Queensland it is probably a good water saving idea (yes, that's me).
I have, however, seen a nifty alternative. In Budapest I remember staying in an apartment that had a gas water heater bolted to the bathroom wall just one metre from the shower. Not only was the water in the pipe already warm from being inside, but there was hardly any water in the one metre of pipe anyway.
I’m not sure you can actually put gas water heaters indoors in Queensland, but one similar solution would be to have your water heater outside the shower wall.
Of course, if all that is a bit much and you still want to save water, you can just buy a diverter valve.