I'm using 1/2" because it is the standard and much cheaper. When I laid these systems in concrete, the engineer would always design a system for 1/2" whenever possible and only used 3/4" if the heat load exceeded what 1/2" could deliver.joeblack5 wrote:I used 3/4 pex with oxygen barrier against the bottom of the oak 1" subfloor. Then there is another 1" oak tongue and groove floor. I wanted 3/4 so that I could have more flow with a smaller pump. Also the larger circumference radiates more. Did not use aluminum plates. Increased the length of the run by zig zagging it in between floor joists. Later I read that sometimes pex in aluminum makes sound because of the different expansion / contraction ratio of pex versus aluminum....
Later J
I'm sure your system works (as was said above, I've yet to hear about one that doesn't) but I have to wonder if there is any real benefit to 3/4" over 1/2"? I have also spoken to dozens of people now that have put this in and any complaints I've heard about noise came from people that DIDN'T use plates . If the plates are installed correctly, there should be zero expansion noise. In any case the 1/2" tubing, plates and manifolds are here so that's what I'll be using.