Changing copper to PEX

[HalM]

Hi,

Shortly I will be doing a tub/shower replacement in our upstairs bathroom. I have to re-plumb the tub and shower and will be adding a new mixing valve and diverter for a hose/wand sprayer as well. I would like to change the existing bit of plumbing from 1/2 inch copper to PEX. But, I notice that the inside diameter size of the 1/2 inch PEX is smaller than that 1/2 copper. Is this anything to be concerned about when doing renos and changing pumbing pipe? Will any pressure be lost? For lines feeding fixtures in a bathroom is there any advantage to change it to a 3/4 inch PEX?

Thanks,
Hal

 

[Terry]

The tub spout needs to be copper without any restrictions or it will push water up to the shower head while running the tub.
Most valves do fine with 1/2" PEX on the supply side. 3/4" is even better.

 

[Sponsor]

 

[Jadnashua]

Using pex will result in a slower fill rate of your tub. As to the shower, it will work fine for one head, but you might notice a little loss of volume if you wanted both at the same time.

FWIW, the pressure is the same regardless of the pipe size unless it is reduced by friction of a high flow demand. Friction isn't an issue as long as you don't try to exceed the rated volumes.

Not all attachment methods are the same when it comes to pex. A fitting that utilizes a crimp means the fitting must fit inside the pipe without anything special. Those that utilize an expansion ring won't. The tubing and reinforcement ring are expanded with a tool, the fitting is inserted, and the tubing collapses back around the fitting creating the seal all by itself. Because the fitting's OD is larger, the ID can be, too, creating less restriction. The beauty of pex is its flexibility and the need for minimal fittings. Don't try to run it like conventional copper and make it look neat, or the additional fittings will overcome some of the benefits, not counting the additional costs for those fittings and potential leak points.

 

[HalM]

The tub spout needs to be copper without any restrictions or it will push water up to the shower head while running the tub.
Most valves do fine with 1/2" PEX on the supply side. 3/4" is even better.

Thank you for the info.

 

[HalM]

Using pex will result in a slower fill rate of your tub. As to the shower, it will work fine for one head, but you might notice a little loss of volume if you wanted both at the same time.

FWIW, the pressure is the same regardless of the pipe size unless it is reduced by friction of a high flow demand. Friction isn't an issue as long as you don't try to exceed the rated volumes.

Not all attachment methods are the same when it comes to pex. A fitting that utilizes a crimp means the fitting must fit inside the pipe without anything special. Those that utilize an expansion ring won't. The tubing and reinforcement ring are expanded with a tool, the fitting is inserted, and the tubing collapses back around the fitting creating the seal all by itself. Because the fitting's OD is larger, the ID can be, too, creating less restriction. The beauty of pex is its flexibility and the need for minimal fittings. Don't try to run it like conventional copper and make it look neat, or the additional fittings will overcome some of the benefits, not counting the additional costs for those fittings and potential leak points.

Thank you for the info.