3 ms·

So, the article correctly says that efficient copper layouts will beat pex, but in residential, those layouts pretty much don't exist in practice. Plumbers are

So, the article correctly says that efficient copper layouts will beat pex, but in residential, those layouts pretty much don't exist in practice. Plumbers are happy to just use whatever fittings, etc, to get pipe where it needs to go, and rarely, if ever, think about the losses caused as a result (i'm really not slagging on plumbers or the quality of work, i'm just saying the average plumber trying to get 4 homes done is trying to get 4 homes done, not sitting around calculating the most efficient layout for copper pipe when he discovers a stud in the way nobody planned for). In the past two brand new houses i've lived in, done to the latest plumbing code, the amount of hilariously horribly copper layout is amazing. (I'm sure anybody who does this for real has ridiculous horror stories). Meanwhile, most pex layouts i've seen perform significantly better in practice just because they use less fittings. So the attempt to be "as horrible as copper" fails. Also pex is a better insulator, so in the real world where pretty much no in-home copper is insulated, pex holds heat better. So, yeah, i agree with the sentiment that well thought out, well structured copper works really well, that doesn't happen to be residential reality, and hasn't been for a long time. (it's possibly a commercial reality though)

petre 9y ago
Pex doesn't insulate as well as PPr (thinner wall) and the fittings always introduce flow resistance and produce turbulent flow since they go into the pipe. Thread fittings for Pex area usually leaky. I would never use them except for serviceable manifolds with easy access, otherwise use press fit fittings. On the other hand PPr fittings go outside the pipe, just like those for copper and they're heat fused. PPr pipes are quite freeze-prone, the walls are thick (6 mm for a DN25 pipe) and glass fibre inserion PPr pipes don't have such a huge thermal expansion as pipes w/o insertion (only suitable for up to 60..68°C = hot water). Most plastic piping is prone to thermal expansion. PPr does not look pretty so it should be probably ran through walls and floors. Copper water pipes should always be insulated with at least 6 mm EPE sleeves or closed cell elastomeric foam sleeves (better). Even cold water pipes should be insulated at least in heated or high humidity spaces because of condensation that forms on the pipe.
- aesh2Xa1 9y ago
  Well, the article explicitly states one should use "outie" style fittings for PEX. Check the fittings figure on the last page; letter (C).
  - japanuspus 9y ago
    Exactly: Modern PEX fitting go on the outside. Where I live (Denmark), PEX is used almost exclusively for new residential installations, but I haven not seen an in-pipe PEX fitting since my parents build their house in the 80's.
    - deleted 9y ago
      [deleted]
- DannyBee 9y ago
  "Pex doesn't insulate as well as PPr (thinner wall) and the fittings always introduce flow resistance and produce turbulent flow since they go into the pipe." Errr, i have used systems of pex with outside fittings forever. Yes, inside fittings suck. All of the manufacturers have been sued for leaking, etc. "Copper water pipes should always be insulated with at least 6 mm EPE sleeves or closed cell elastomeric foam sleeves (better). Even cold water pipes should be insulated at least in heated or high humidity spaces because of condensation that forms on the pipe." Yes, they should. But they very rarely in my experience (or they did a super shitty job) are unless the house was just built and you had a good code inspector
deleted 9y ago
[deleted]

petre 9y ago

Pex doesn't insulate as well as PPr (thinner wall) and the fittings always introduce flow resistance and produce turbulent flow since they go into the pipe. Thread fittings for Pex area usually leaky. I would never use them except for serviceable manifolds with easy access, otherwise use press fit fittings. On the other hand PPr fittings go outside the pipe, just like those for copper and they're heat fused. PPr pipes are quite freeze-prone, the walls are thick (6 mm for a DN25 pipe) and glass fibre inserion PPr pipes don't have such a huge thermal expansion as pipes w/o insertion (only suitable for up to 60..68°C = hot water). Most plastic piping is prone to thermal expansion. PPr does not look pretty so it should be probably ran through walls and floors. Copper water pipes should always be insulated with at least 6 mm EPE sleeves or closed cell elastomeric foam sleeves (better). Even cold water pipes should be insulated at least in heated or high humidity spaces because of condensation that forms on the pipe.

aesh2Xa1 9y ago
Well, the article explicitly states one should use "outie" style fittings for PEX. Check the fittings figure on the last page; letter (C).
- japanuspus 9y ago
  Exactly: Modern PEX fitting go on the outside. Where I live (Denmark), PEX is used almost exclusively for new residential installations, but I haven not seen an in-pipe PEX fitting since my parents build their house in the 80's.
  - deleted 9y ago
    [deleted]
DannyBee 9y ago
"Pex doesn't insulate as well as PPr (thinner wall) and the fittings always introduce flow resistance and produce turbulent flow since they go into the pipe." Errr, i have used systems of pex with outside fittings forever. Yes, inside fittings suck. All of the manufacturers have been sued for leaking, etc. "Copper water pipes should always be insulated with at least 6 mm EPE sleeves or closed cell elastomeric foam sleeves (better). Even cold water pipes should be insulated at least in heated or high humidity spaces because of condensation that forms on the pipe." Yes, they should. But they very rarely in my experience (or they did a super shitty job) are unless the house was just built and you had a good code inspector

deleted 9y ago

[deleted]