comparisons
Hi SR. I happen to know quite a bit more about the noritz than they would like me to know. I rep'ed them for 5 years, did there local training classes and got to trouble shoot installations as both and installer/plumber and rep. So this is the background where the below comments come from.
First thing I want to say is that YES! this is a very high quality product period and I take nothing from them. If you have one, you'll be happy. Now as for the claims:
Manufacturer's tend too over state aspects somtimes and as the past rep I can tell you that many will "parrot" these without looking further into it. (I was once guilty of this but have learned better) Below are some things you might not know.
Hi Scot, I even ran into some DIY installed ones where the run was over 100' of ¾" pipe with the furnace and range attached. Had to run a dedicated line from the meter to the unit. Also seen many undersized gas meters. The local gas company is more than happy to upgrade the meter.
Now as to make of Tankless water heaters, I have to say Noritz is by far the best out there. It is more advanced than the Rinnai, comes with parts that Rinnai does not like the advanced controller. Now Rinnai is a for off second choice for me, then even farther off third is Takagi, I would not even consider any of the others.
Lets compare the Rinnai R75LSi / GE 75DNSRSA to the Noritz N-0751M-DVC
BTUs
Noritz 11,000 - 199,900 Rinnai 15,000 - 180,000
Flow rates / temp settings.
Noritz .5 gpm - 9.8gpm 100º - 180º Rinnai .6 gpm - 7.5 gpm 98º - 140º
Noritz can be set to 180º with out any special controllers, the Rinnai needs a special remote that needs to be purchased. Also Rinnai's min flow rate can vary from .6 gpm to 1 gpm
Response: Only True if you consider incomming water temperature. If the incomming water temperature v/s set point is too close and by that I mean under a 20*F rise, the units will require a higher flow rate to activate. BOTH of them! They don't tell you that in the literture because it really does not matter in a domestic water application. Even with recirc comming back at high temp, when there is a demand, the mixed water temp into the unit will drop and you are right where you started. The only part of this that is is accurate is the .5 v/s .6 activation rate dn that is splitting hairs. If the salesmen tell you different they are either not being entirely truthfull or do not know the product very well.
Now as for max temp, that is for a reason. Rinnai chose to do this for safety. Setting a DHW for over 120* can create scalding hazzards and at over 140*F in a house is just nuts. In fact in many areas, inspectors are making contractors place a lock box over controllers that allow higher than 120*F. I think this is overkill but you know how fun arguing with an inspector is.
Vent piping
Noritz uses 100% stainless and is adjustable. Rinnai uses galvanized steel or plastic and requires cutting to adjust the lengths.
Response: Rinnai's concentric vent is direct vent meaning it bbrings combustion air from outside and exhausts to outside which also means it will never have combustion air issues or that it is highly unlikely. It is a heavy wall aluminum inner with a light PVC outer. It cuts easily and does not require a special "slider" that must be of the right length so you don't have to carry as many different parts on the truck.
N-vent is easy to use, push joint and quality suff but you have to have a slider of the proper length on anything other than the "up and out" instalations and can never cut it.
To me the advantage to a true concentric vent is you can put it anywhere without worry about what else is in the air. I have a N-132 in a Pizza place so packed with four that you could opened a bread shop! I also have seen them in hair salons and closets with other issues from combustion air. For those application you have to go to a DV series unit (Direct vent) and then cost becomes more of a factor and the venting goes up. Not a hughe deal if you know when you need it.
I personally think that the concentric vent is rinnai's biggest advantage. THat's more my personal preferance.
Heat Exchanger
Noritz heat exchanger is 25% thicker than the Rinnai's
Reesponse: I think this is BS. You cut them both, mic them and then tell me. This is a pitch Noritz uses comaring them to others. Yes, they ARE 25% thicker than others...but not Rinnai and I don't think they are mentioning names. At least they weren't.
Burner
Noritz uses a duel flame burner which gives a better temperature stability. Rinnai is still using a single flame burner.
Response: They both garuntee within 2*F of setpoint. Both work very well at delivering.
Controls
Noritz comes with a controller that gives you full diagnostics. Rinnai must purchase a special remote.
Response: Total BS. Both Remotes give full diagnostics. Anyone who told you different is simply not telling you the truth.
Additional Features
Noritz allows you to make a simple elevation adjustment by just clipping two wires together, the Rinnai you need to set the dip-switches. Noritz also has a built in controller for recirculation pumps where the Rinnai does not.
The one thing they do have in common is the warranty 12 year heat exchanger/ 5 year parts/ 1yr labor
Resonse: Elevation setting is one dip switch "click" v/s one wire plug. Not a big difference there, especially since you already have the cover off for wiring on either one. The controller for recirc is nice, however both still take a warranty hit to 3 YEARS when recircing through the heater except for the ACT Metlund D'mand system (Which can not use the control anyway) I would not use that feature anyway and always advise on using the Metlund on any tankless water heater regardless of brand as it does not shorten the life, void the warranty or cause an increase in energy consumption.
On Parts warranty,(unless things have changed in the last two years and as an authorized service provider for Rinnai and Noritz) Noritz will have you buy a part and pay FT, then you ship back the old part and they will give you credit if it's warranty. So Far any Rinnai Part I ever saw shipped was overnighted at no charge and there was no further paperwork to do. I have also seen Rinnai ship out FREE Heat Exchangers a couple of times where there was a failure due to inproper installation and condensate damage when everyone knew full well that is was not actually warranty. That's pretty good.
The Nortz is a very well made product and it is no accident that Rinnai and Noritz represent about 70% of the world wide tankless water heater market! Who is bigger depends on who you ask.
I will note this though, look on the Japanese stock Exchange Nikkei and you will find Rinnai in the top 500. None of the other manufacturers are there. This is not because of tankless, Rinnai happens to be the worlds largest mfg'er of GAS FIRED appliances. In the US market they hold about a 52% market share with Noritz being second at somewhere like 20 something. I forget the exact numbers. The others are not even close and there is about a dozen or so of them. This is as much marketing as anything else.
The Rinnai Tech support is still superior with 24/7/365 v/s Noritz 8am eastern to 5pm pacific monday through Friday and how good a engineer you get at either is subject to who you get. They are both great tech support and far better than any of the others.
In a nutshell, in my opinion you Noritz and Rinnai, and Apple and an Apple. Both great products.
One more thing I forgot to mention, in a modern home with 3.5 baths or less with standard shower heads (flow restrictors not removed) you only really need about 5gpm capacity of hot water. The showers actually only use about1.5GPM of water even though the heads are marked for 2.5. Because...they are rated at 80PSI in a lab. You are going to be in a house, not a lab and not at 80 PSI. With system losses you're lucky to get 1.5gpm. If your velocity is good and temperature steady, you have a happy HO. Body sprays, rain heads and other things of course can be factors. If you have a big tub, while filling it, it might take a bit longer but so what? once it's full, you're still not out of hot water. Any of the Noritz or Rinnai units that will do 5+GPM of hot water at a 60*F rise will do a great job in the bottom 50% of the USA in a typical home. For the colder climates, look for a model with a bit more capacity.