Over the last couple of years we have worked on sealing the house better (new siding with house wrap, new windows / doors, caulk, insulation etc), replaced the 2 HVAC systems with a single variable capacity zoned system, sealed the crawl space and replaced the garage doors with insulated doors. Now on to the plumbing.....
Our split level home was built in two phases, the two story (living quarters above garage) and then the main floor (over crawlspace). There is a mixture of CPVC, PVC and polybutylene. The PVC is holding up well, the poly has a couple of seeping joints and the CPVC is getting brittle. On the main level the genius builder put the water lines in the attic. We currently have two small tankless water heaters located within the living space and vented through the ceiling / attic / roof. Each water heater is only good for running one appliance at a time, they both have standing pilot lights and have no efficiency rating.
I am starting the project with a new water heater, a Rinnai RUR199iP. It is Energy Star qualified with an energy factor of .96. It should save us on propane, not enough to offset the cost but that is not the only reason we went with a new heater. The current heaters require a minimum flow of .5 gpm to activate which makes it hard to get hot water out of a faucet at a low rate. The new heater will activate at .25 gpm. Also, the new heater will direct vent, it vents right out the back wall vs having a vertical vent through the ceiling / roof. This will further our ability to seal up the house.
I am using PEX throughout the house, replacing all the old various pipes. I can't decide whether to have a manifold with all home runs or to run a loop through the house. The water heater has a feature that can be enabled that circulates hot water so you have near on demand hot water. I would imagine this would reduce its energy efficiency though. I need to read up on this.
Anyway, here is the new water heater installed.