We are renovating all the bathrooms in our house that was built in the early 70s.

The plumber has replaced most of the copper pipes with PEX tubing. He has not replaced copper entirely and has coupled copper with PEX (see pics below). He connected the main water supply copper pipes to 1/2" PEX but then connected them to 3/4" PEX later.

Shouldn't the main supply line be connected to the wider PEX if at all? How does one check that the clamps are properly fixed onto the connectors?

He has run PEX right next to main heating duct from the furnace in the mechanical room (that supplies heat to the house) and in other places as well. Is this safe? Is a minimum clearance required between the PEX and heat vents?

Please see pictures of the shower rough-ins in two bathrooms. Is it normal to have so many joints and connectors? Any thoughts would be most appreciated.

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  • 2
    So many elbows... that pex pipe can be bent neatly with a spring and it will reduce the losses and noise.
    – Solar Mike
    Nov 14, 2019 at 7:49
  • 1
    Wherever the pipe passes through a stud make sure a mailing protection plate gets added, on both sides if possible. Nov 8, 2020 at 12:58
  • I'm sure that wet wall isn't structural, but Oy! those notches! I'm sure it took much longer to cut those than it would have to simply drill a hole...
    – FreeMan
    Mar 8, 2021 at 11:57

2 Answers 2


Great questions! Yeah, I agree that the 1/4" AIN'T RIGHT. Have him replace those sections. A body-spray setup needs all it can get.

Being close to Ductwork is fine, the hot water is hotter than the ductwork will ever get. FYI, the Blue PEX is just coloring and is exactly the same as the Red PEX. However, PEX cannot withstand a furnace flue's/exhaust pipe's temperatures, ensure PEX is not touching nor even within 2' (my requirement) of that Ductwork.

Yes, there is a way to test the Plumber's crimping workmanship. It's a Go/No-Go gauge and he should be using one himself...likely molded/carved onto his crimper. See https://www.menards.com/main/plumbing/plumbing-tools/pex-tools/nibco-reg-go-no-go-pex-crimp-gauge/px01382r1/p-1444449294533.htm

So many fittings? Yep, kind of kills the "PEX advantage", doesn't it...soldering ain't slow and only gets A LOT faster in your kind of shower setup. I'm not a fan of PEX. It's only good for 50-years and copper is good for OVER 100-years (in most areas)...which house would you buy...sell in 20-years or less.

By the way, while you have some access to duct joints, liberally wrap the joints with Aluminum Foil Tape...the real duct tape.

  • 1
    What is the basis for the statement that PEX is only good for 50 years? Nov 3, 2021 at 14:16
  • 1
    PEX has only been around for ~50 years, so most sources online use that as an "average lifespan" metric, because PEX pipes installed then are still around. However, it should be obvious that that's not a particularly accurate definition. It's true we do know copper can last 100 years, because we've seen it, but it can also last much less time. PEX, in lab testing, has similar "life expectancy" to copper (100 years). But for both copper and PEX (and CPVC, too), the main limiter on life expectancy isn't the pipes themselves, but the conditions you subject them to.
    – TylerH
    Nov 3, 2021 at 15:23
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    Introduce acidic water or sub-zero temperatures to your copper pipes and they won't last very long. Send 180F / 82C (or hotter) water or chlorine water through PEX pipes on a regular basis and they won't last very long, either.
    – TylerH
    Nov 3, 2021 at 15:26

It's best practice to pipe insulate your pex 24" or so in either direction of direct contact with duct work, weather that duct work is insulated or not. Especially in moisture rich environments, heat exchange can cause condensation build up. with enough time moisture damage can occur. High humidity geography expedites this process. Unless you've perfectly enveloped the building. I've witnessed this in the southeast US on multiple damage repair projects.

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