BoyntonStu wrote in news:4b15316c-ea49-46e5-9bd1-
:

A 9 KW tankless HWH manufacturer claims that it is sufficient for a
whole house at up to 3 GPM.

snip
Efficiency: Tankless is slightly more efficient.

Location - I am in Florida where the input temperature is 70*F.



Yet another option :

http://www.geappliances.com/heat-pump-hot-water-heater/