Alright everyone I really do need help on this one. Just got a whirlpool installed in the home that is 120 gallons. The 85 gallon water heater we have currently clearly won't be able to work at all and it doesn't. About half way into filling the thing the water starts getting cold. There are soooooo many different opinions and articles on this that it gets quite confuzing. One says tankless are excellent while another says they are horrid. I live in north dakota by the way. Not sure how cold the water is but it probably is somewhat cold. It seems like the veridict on this forum is that the tankless do save money but that will have to be considered with the initial cost of installation etc.

I was looking at the commercial grade rheem model gt199dvn. It has a 80 degree rise at 4.1 gpm. That should be plenty. Cost of unit is around 1000$.

What about maintenance of these things too etc.

Any help would be much appreciated. Thank you.