kinda late but I hope this will help somebody.
I am a general contractor and property manager for both residential and commercial.
Not a salesman for anybody but myself.
i have a client that had one of these units installed in a small brick 2 bedroom bungalow for heat (hydronic cast rads) and DHW, the house is located in Toronto Ontario.
we have some pretty cold water here in the winter so recovery and rise is very important.
The NTI has been in service for about a year now and has worked quite well for their purpose and they are very pleased with the unit.
no problem with luke warm at any time for that matter they had to have the output from the mixing valve turned down as the water was coming out at about 135.
The big deal for them was the fact that the unit is so quiet.
When going tank-less, be careful and don't be cheap, i have had a couple of clients that did and went back to the tank. they bought cheap and didn't have the unit sized properly.
Hope this helps somebody.
DC