What are the advantages/disadvantages of Pex tubing? How does it compare to copper?
From Pex Information:
- Flexible PEX tube is manufactured by extrusion, and shipped and stored on spools, where rigid plastic or metal piping must be cut to some practical length for shipping and storage. This leads to several advantages, including lower shipping and handling costs due to decreased weight and improved storage options.
- PEX plumbing installations require fewer fittings than rigid piping. The flexible tubing can turn 90 degree corners without the need for elbow fittings, and PEX tubing unrolled from spools can be installed in long runs without the need for coupling fittings.
- Attaching PEX tube to fittings does not require soldering, and so eliminates the health hazards involved with lead-based solder and acid fluxes; PEX is also safer to install since a torch is not needed to make connections..
- PEX resists the scale build-up common with copper pipe, and does not pit or corrode when exposed to acidic water.
- PEX is much more resistant to freeze-breakage than copper or rigid plastic pipe.
- PEX tubing does not transfer heat as readily as copper, and so conserves energy.
- Water flows more quietly through PEX tube, and the characteristic "water hammer" noise of copper pipe systems is virtually eliminated.
- PEX plumbing installations cost less because:
- PEX is less expensive than copper pipe.
- Less time is spent running pipe and installing fittings than with rigid pipe systems.
- Installing fewer fittings reduces the chances for expensive callbacks.
If you are only going to be doing a little bit of work, check with your local rental stores, you may be able to rent the tool for a decent price.
Another advantage to PEX if you're doing a from-scratch installation is that it's typically installed using a manifold at the water source with a run to each faucet. That approach significantly reduces pressure loss at one faucet when another faucet on the same branch is turned on, as often happens with copper plumbing.
You could do the same thing with copper, of course, but it would be prohibitively expensive in time and materials.
A huge disadvantage with PEX is that it is semi-transparent. If your water supply has nutrients in it and the PEX is installed so that light will get to it, you will find that algae (green), bacteria (black, orange or yellow) will grow inside it. It sloughs off in long, stringy goop similar to the biofilm that grows in diesel tanks that haven't been treated to prevent bacteria growth. Keep it well hidden in walls and away from crawlspace vents where sunlight can penetrate.
Keep squirrels away from it, they find it delectable.
Also another advantage listed is that there's no lead. That's true insofar as you stay away from the type that requires brass fittings.
Otherwise, you have a highly flexible, smooth bore water supply system that will allow for using smaller tubing, which can speed up hot water temperature delivery. It's cheap enough that you can do end-run (star) delivery to a central control manifold, typically each run will only have two joints, one at the manifold and one at the the coupling to the shutoff valve. You also don't have a problem with meth addicted copper thieves coming and stripping your house plumbing out if you leave it unattended (summer cottages, another reason iron ain't so bad).
There are many examples of building products that claimed to be "the wave of the future" and turned out to be utter failures, sometimes dangerous. (polybutylene plumbing, aluminum wiring, and asbestos building products to name a few.) Despite the manufacturer's glowing claims, the actual long-term characteristics and behavior of PEX tubing cannot yet be known.
One of copper's distinct advantages is its long history of solid performance and desirability.
I know PEX is cheaper (specially considering the rising price of copper), easier to run and less noisy than copper but you have to buy a special crimping tool for the fittings (don't know how expensive the tool is). My only fear would be long term effects depending on water type. For instance I have very hard water (very high calcium content; I should NEVER have to worry about osteoporosis) and I wonder what will happen 10, 15, 20 years down the road to the PEX pipe based on the minerals in the water.
I'm also not sure if there are any long term health effects from having water run over PVC. Not sure what kind of chemicals leach into the water over time. I'm 99.99% sure it's safe though.
Get a pinch clamp tool, like this one, and a pipe cutter. Those are the tools you'll need. One tool works for all size pinch clamps.
- Copper has antimicrobial properties.
- Copper will oxidate and leak under certain water and electrical conditions.
- Copper that is not completely dry and clean cannot be soldered.
- Pex can be fixed underwater and covered in poo.
- Out of the 1000s of pinchclamps I've installed, not one has leaked.
- Pex fittings can be easily undone and reused, just heat the pipe slightly.
- Out of the 10 sharkbite fittings I've installed, one leaked.
If you have to use a slip on style fitting, smear the outside of the pipe with plumbers grease.
PEX tubing has much much better freeze burst resistance properties than copper. Its very important especially for people who lives in cold climate areas.
There is a notable potential downside with PEX (and I'm saying this as someone who's chosen it for his own house).
PEX has the lowest strength of the three most common materials. If I recall my numbers correctly, copper will burst at something over 5,000 PSI. CPVC at around 3,000, and PEX at around 1,200.
Of course, if you get 1,200 PSI in your system to begin with, you've got bigger problems. But still...
Here in upstate NY (it's -12 tonight which I will admit is unusually low) the risk of copper is freezing and bursting. That happened to me many times until I discovered Pex, which will expand several times its size without breaking and then return to its normal size. (Hmm, what does that bring to mind. But I digress.) Pex is so easy to work with and so much cheaper than copper, I don't know why you would not choose it. BTW, I have taken other measures to prevent freezing -- our hot water heating system is still copper but we have put in antifreeze, which works well. But, of course, you can't do that with domestic and live to see Superbowl 51. Use Pex.
Copper piping has been around for at least 60 years and the only time you get pinholes in copper is because you probably used the wrong thickness of copper. If a solder joint is properly soldered then it will never leak. Ive been working on domestic hot water systems of every size for over 40 years and have never had any build up of any kind on the inside of the piping. That usually only happens on the larger street mains because the water moves slowly compared to a house. Copper has withstood the test for over 60 years. Pex can not make any such claims. It may be cheaper but it it may cost you in the long run. I would take copper over pex anytime UNLESS there is a good chance the pipes could freeze. I know pex can stretch much wider then copper and return to normal size.