The cheap ones are fairly common in Britain where the user isn't choosing (student houses, cheap rentals etc). The installation cost is low, but the running cost is high.
They are crap. 8kW is typical, and the pressure for a reasonable water temperature is low.
I haven't knowingly used a more powerful one. I suspect that would negate the cheap installation cost, as it would need a three phase circuit.
Yes, You can buy an electric tankless but just be extremely informed of the large amperage requirement to instantly heat your selected gallons per minute flow.
Yeah you can find them on the Home Depot site. The largest ones use 36kW which is beyond a typical residence's electrical service. It doesn't save you any money if you need to upgrade your electric service.
