Jadnashua
Retired Defense Industry Engineer xxx
Pressure is the same regardless of the size of the pipe...volume on the other hand can change radically. 1/2" pex is smaller interior dimension than 1/2" copper. But, it is smoother, and is usually installed with fewer fittings, so the end result is it can flow nearly as much. If you are worried about volume, run 3/4" pex, but 1/2" should be okay in many situations, especially if you use a manifold with home runs. Or, run 3/4" to a manifold in say the bathroom, then 1/2" to fixtures.
If you are going to have a mega shower with numerous heads or a big soaking tub, then go 3/4" and consider a 3/4" valve as well.
If you are going to have a mega shower with numerous heads or a big soaking tub, then go 3/4" and consider a 3/4" valve as well.
