I have had a noritz tankless water heater for 2 years, model N-0931M. It has worked flawlessly until it started throwing C-90 codes---venting/fan problem. I have absolutely no complaints about the product, I have plenty to say how Nortiz treats its customers. They do not return calls, they don't care that I am taking cold showers, they do not have factory reps for the tough probems that the contractor cannot handle. This means if you have a good product but no factory or company central support then do not buy Noritz. Now unless I want to get an attorney, I will be forced either to convert back to a tank or get another, more carefully researched brand. WOW Either way I am going to eat the money