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Which pipes for new home build?

Posted by toddao (My Page) on
Thu, Jun 24, 10 at 17:37

We're building a new home in Atlanta that will be on municipal water. The house will be about 4000 SF with a full basement and two levels above. We're trying to decide between copper, PEX and CPVC. I've been reading about the differences and I'm leaning toward PEX with homeruns and manifold. But I understand that you can't use a recirculating pump for instant hot water with PEX. I'm not sure how necesary this will be, but I'd love to not have to waste so much water waiting for hot water. Is this less of an issue with PEX, or if not, are there any solutions? Appreciate any feedback.

Follow-Up Postings:

RE: Which pipes for new home build?

I have PEX in my home and Love it. The water heater is situated just below the master bedroom so in the morning I never have to wait for HW. I do have to wait at the kitchen sink which is about 30 feet away and it is only a problem when using the dishwasher. I let the water run in the sink for about 20 secs til I get HW at the sink, this way the dishwasher gets HW right away. PEX is naturally insulating, but if the water sits 24hrs between usage, it will obviously be cold.

So why can't you use a recirc pump with a PEX system? If you run a separate recirc line, why not?

Take Care,


RE: Which pipes for new home build?

Thanks for the info Dan. In terms of not being able to use a recirc pump with PEX, I see now that my builder or his plumber were not well informed. I suspect that you can, and I will research it further.

RE: Which pipes for new home build?

The problem with the recirc pump isn't with PEX, it's with the home run to a manifold design. You can use PEX with a branch design system also - which will work with a circ pump.

Design your plumbing so that you aren't wasting water or energy. Avoid long hot water runs, insulate all hot water pipes and consider a small, point of use heater in series with the main heater for those runs that are long and isolated - such as a kitchen or a master bath. A circ pump that is on for a minimal amount of time can save water- but be sure that all of the lines, including the return line, is insulated.

RE: Which pipes for new home build?

I don't think anyone would say PEX is "naturally insulating" if their main water line was 30' of PEX over an uninsulated garage and they lived in So. Louisiana. It's common in new construction, and I can't believe it isn't a code violation. Sleeving it with those little foam tubes is futile. The only thing that gives some relief is to roll R30 batts above and below it. That really does improve on the 30 sec of 120F water that otherwise comes out of the cold water line on hot summer days when you don't use the faucet every 20 minutes or so...

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