3/4 PEX or 5/8 Pex THE DIFFERENCE?

anthony_7

I am going to run pex to my second floor baseboard. I want to know if its much of a diff if I use 5/8 or can I use the 3/4. I would prefer 3/4 as I also can use it for the potable water supply to the second floor upstairs.

Any issues.

hot_rod

fittings

are one concern. Seems the 5/8 has limited selection for plumbing work. Supposed to be a bunch of 5/8" crimp ring fittings on tyhe market real soon

It all comes down to flow rates and pressure drop. For some reason 3/4" pex seems twice as hard to work with as 5/8" for baseboard runs! If the 5/8 can accomadate you load and loop lengths, I suggest it for the heating.

Plumbing wise I like the home run Manablock type systems. All the tube manufactures have a version of this. Looks like Wirsbo has a new modular plastic plumbing manifold out. This allows you to use 3/8" tube in many applications. It also keeps the system "fitting free" behind the sheetrock.

hot rod

Steve J

5/8\" or 3/4\", 5/8\" hands down

is the choice I would use just for the ease of use. 5/8" PEX will have similar flow rates to 3/4" copper, smoother inside walls (less friction) and able to be bent in a 90 degree elbow instead of a fitting (again less friction).

Like hot rod said, just make sure it can handle your flow rates and overall length, for example using a 15-42F circ, and a 20,000 BTU load (approx 33' of baseboard) maximum length of 5/8" PEX would be 290'.

Same scenario, you could use 1/2" PEX but the overall length is limited to 100 feet.

Dave H.