I am trying to select a natural gas water heater to install into my house. It has to service two bathrooms with showers and two kitchen sinks, a dishwasher, and a washing machine.
I've narrowed my selection down to three:
- Rinnai RUC98i (max 199k BTU, 9.8GPM)
- Noritz NRC1111 (max 199k BTU, 11.1GPM
- Takagi T-H3 (max 199k BTU, 10GPM
My application is indoor, and my plumber told me to look for a "direct vent" model because we want to vent horizontally to the exterior of the house (distance < 3') instead of going up through a second floor and a metal roof. This leads to the question: how do I evaluate the venting options? It seems that at least two of these models support multiple venting types, and I have no idea how to evaluate them. For example, the T-H3 overview has a bullet that states:
Venting with Schedule 40 PVC, CPVC, PP, Category III stainless steel
I like having options, but there are 4 different things there and I don't know how to evaluate them.
Is there a particular advantage of concentric stainless steel over PVC or vice versa? Is concentric PVC even a thing?