Are there any advantages to using copper rather than CPVC or PEX?
- Copper has a well-proven track record
- Copper parts are more readily-available and it's easier to repair (eg, don't need the expensive crimping tool like with PEX)
- Safer during fires since it is much more resistant to heat and giving off fumes
That said, I am a huge fan of PEX. It's been around for quite a few years now (though obviously nowhere near as long as copper), and for the most part is proven.
- Pex is cheaper (in both material and labor costs),
- Pex is easier to install, with many less connections required (eg, try doing a long straight run through a wall or perpendicular through joists - PEX slides right in, copper requires a ton of little segmented pieces and couplers)
- Pex can look better when properly installed (when not properly secured, it sags, and because of the forgiving nature, you can have crooked lines and non-right angles).
PEX can be used for troublesome water supplies that will pinhole copper.
From my experience, Copper is NOT RECOMMENDED for hot water circulating system. I'm having to replace my entire plumbing distribution system due to pin hole leaks near solder joints in the hot water recirculating system. The leaks are never in the joint, but typically a 1/4" to 2" away, always associated with an area showing green corrosion and usually where there has been the spread of the flux and solder. I'm on my 6th leak in 6 months... while waiting for insurance settlement to come in to repair all of the leaks in the ceiling. No leaks in the cold water distribution...but i'm replacing both. I've HAD IT with copper.
There doesn't appear to be a concensus as to what is causing the pinhole leaks, but it's a nationwide problem. Plumbers say "not our fault" bad material.... suppliers blame in on chinese copper pipe and fitting ... or the turbulence of the water. As near as I can tell it is caused by EXTERNAL corrosion that is accelerated by the warm temperature of the water and the solder flux that is oxidizing the exterior of the pipe. I call BS on the rationale that says its due to corrosion due to the moving water.