# PEX: Expansion vs Compression



## Hauki (Jan 3, 2009)

My house is 103 years old and has a nice mix of rusting galvanized and some copper updates. My plan is to gut the galvanized from the meter out with PEX and have been looking at and reading about expansion (Wirsbo/Uponer) and compression (various suppliers) systems.

I have scanned back a few hundred postings but haven't really seen any definite opinions on one vs the other. No doubt there are schools of thought on this and since I have a choice, I'd appreciate your expert opinions.

I'm certainly no plumber but I've done lots of small jobs (replacing toilets, sinks/faucets, tubs) on the house using copper however I have never used PEX. Also, I'm assuming I'll have to do a pressure test upon completion and have never done this so will I need a plumber for this last part?

Thanks.


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## II Weeks (Jan 6, 2009)

I've used both and for my home I would only use the expansion type. I like the Everloc system.

Just at the difference.


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## Termite (Apr 13, 2008)

If you're paying a plumber to do it, demand the expansion type. There's no restriction of flow at the fittings like there is with the crimp type. 

For a DIY job, it depends on how much you want to spend. The tool to do the expansion type is pretty spendy. The tool to do the crimp type can be bought as a kit for less than $150. 

Personally, I have the crimp type and have done most of my house in it. I've had NO leaks, and no problems of any kind. I removed 1/2" copper to put in the PEX, and had no noticeable reduction of water flow due to the 3/8"i.d. crimp fittings.

Either way you can't lose. If I had the money I'd opt for the expansion type, but I almost never see them used around here (for reasons I can only attribute to cost???). I regularly inspect homes worth several million dollars, and even the guys that do them are using the crimp type.


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## tiggerphil (Feb 16, 2009)

The expansion fitting is superior of the two fittings but would most likely need to be installed by a professional as the tools are costly. The down side to insert fitting is the volume of flow. This usually only comes into play with high flow fixtures such as tubs and hose bibs. If you are doing the job yourself and are using insert fittings make sure that you keep the pipe sizing larger up to or close to any high volume fixtures.


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## badgerlandcable (Sep 26, 2011)

I have some plumbing that I have to remove from a soffit and think going the pex route is the way to go. I was planning on using the crimp systems at Home Depot / Menards.

How much larger should the pex be to accommodate the same size copper?

Is it generally wiser to convert from copper to pex in the basement and then run new lines all the way to the fixture . . . as to not have connections in the wall / floor?

Thanks in advance.


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## Daniel Holzman (Mar 10, 2009)

This topic has been discussed many times on this forum. I would read the posts regarding how "touchy" the crimp fittings are. Some have noted that you should not mix brands between the pipe, the fitting, the compression ring, and the compression tool. Personally I have used the Uponor system extensively with relatively little trouble. I put up a lengthy post about 6 months ago discussing issues with the Uponor system, and how to get around them, I will not repeat the post here. Just as a note, I only use Uponor fittings, and I do not use brass fittings (I use plastic) unless absolutely unavoidable, primarily because of historical problems with brass fittings and dezincification (see Zurn lawsuit).

Tool price is a potential issue, I paid about $300 for my expansion tool, but when you consider that I did an entire house in PEX, the tool price was a relatively small part of the total picture. I think the flow reduction is not a major issue for the crimp system, as you are not going to have a lot of fittings in the system, unless you are careless about arranging your PEX. A bigger issue in my mind is long term reliability, in terms of leakage. I am not entirely comfortable with crimp fittings, given issues I have had in the past with compression fittings on copper line. I have used a few shark bites where I wanted a disconnect, and they have worked fine, but of course they are very expensive and not suitable for a whole house. I would investigate use of brass fittings, they have a bad history of leakage and premature failure.


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## Work4living (Nov 28, 2010)

I have and still install both systems. Flow reduction is a never an issue. Expansion type is about double the cost of crimp. Availability of fittings is less with expansion, more with crimp. You need to be certified with the expansion, or you lose your warranty. Bottom line as for plastic or brass fittings, Plastic has limits, sunlight, chlorine content of water, etc.....

There is no manufacturer of anything that has not had its share of a lawsuit. My best advice, Dont look for the cheapest way out. Go to a true plumbing wholesaler, not a big box store. Stay with class a or b PEX tubing. Run your lines in a homerun method instead of a conventional system. Flow rates will be well above average in 1/2" PEX vs 1/2" copper.

Read the manufacturers' warranty, installation requirements. Above all if you are in doubt....Hire a professional.


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## TheEplumber (Jul 20, 2010)

Most plumbers in my area, including me, crimp their fittings. But if you want to buy that $300 Uponor tool, scrap your copper pipe to pay for it :thumbup:


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## Homerepairguy (Aug 1, 2010)

Hauki said:


> My house is 103 years old and has a nice mix of rusting galvanized and some copper updates. My plan is to gut the galvanized from the meter out with PEX and have been looking at and reading about expansion (Wirsbo/Uponer) and compression (various suppliers) systems.
> 
> I have scanned back a few hundred postings but haven't really seen any definite opinions on one vs the other. No doubt there are schools of thought on this and since I have a choice, I'd appreciate your expert opinions.


You didn't mention tool cost but maybe think about this:

Say a crimping tool costs $150 and an expansion tool costs $300. Since you have to buy a tool regardless, the expansion tool really only costs $150 more. Don't look at it like it costs $300.

With that in mind and all the money you will save by doing the job yourself, the $150 is a drop in the bucket so don't even think about the tool cost when making your decision on whether to go with the expansion or crimp systems. Make your decision purely on which system you think will work best for you.

FWIW, I went with the Uponor Aquapex system and bought my expansion tool for $289 and all my PEX materials from pexsupply.com. I liked the fact that all materials come from the same manufacturer and that there's no "go-nogo" testing of joints required. Expand, install, forget with peace of mind for a diy'er.

Other's milage will vary,
HRG


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