Hot water

[FossilPhill]

Well, we never did find out what kind of heater op has. If it's a heat pump.. ivevheard they can be pretty slow to re-heat.

That depends almost entirely on the ambient temperature, and if they have resistive heating boost.
I have a brand that has no boost at all, and it can take a few hours to reheat if the ambient temperature stays below 10C (50F), however, on a mild day of 75F it is much quicker, especially if humidity is higher.
Sized correctly, so that water does not need to be re-heated at night, and run via a timer that allows only daytime running, they can be incredibly cheap to run, especially if they are run from rooftop solar power.
Of course running costs get harder to calculate if you live in an area where the cost per Kwh depends on the time of day (smart meter) and there is no rooftop solar power.

 

[Twowaxhack]

Depends on how cold the incoming water is for sure and if heat pump what ambient temp is.

All fluff……get a 4500 watt standard water heater and install a restrictive showerhead.

Save the world you wasteful pigs