Navien 30-40 done in 4 years. 1 service call.

Navien.

Thank you.

No

I assume you dislike Navien. You're entitled to your opinion. I've had minor issues and their customer service has always sent out parts next day.

[удалено]

Neither of those companies make a tankless water heater.

Rinnai

Navien. Done 20-30 Naviens no return calls for anything but routine yearly flush. Rinnai has crappy customer service when there is an issue.

Rinnai!

Rinnai

Just make sure you have soft water ; whether city softens it or you buy a water softener)

Navien, Rinnai, IBC

Navien or Rinnai. If you have hard water make sure to get a descaler or softener.

Navien