People have no idea about the physics of energy
A lot of coal is burned for domestic electric hot water.
Even gas heaters spew carbon into the sky.
I often turn my water heater off overnight, turning it on an hour before I want to shower or wash dishes.
Amazingly, two educated men I told this, claimed it was better to leave the power on, because "you waste energy heating up the water which has gone cold"
Even more amazing, one was a Physics graduate!!
For the record folks: Its always better to let the water go cold
if you dont require hot water.
The input energy is used for these ends":
1) hot water in the shower or basin ie this is NOT wasted
2) waste heat escaping from the water heater
3) waste heat escaping from the pipes.
Now heat escapes with some exponential of the temperature. ie hot water in the tank means much more heat is escaping
, despite insulation.
So keep the water as cold as possible for as long as possible.
Huge savings are possible if every water heater had a time switch.
The big point I am making here: We can save the world only if we use less energy.
However most people, even Physics graduates, have a woefully inadequate
understanding of energy and thermodynamics.
Without conservation, heat exchangers, and 30kph
transport, this oil-civilization is headed for the crapper.
Without understanding, the population won't embrace conservation.(I have seen claims that pipe cladding is not cost effective despite 3)
maybe 'cost effective' will change when Saud stops pumping, or carbon costs are internalised)