# insulating pex pipes



## ibs325 (Nov 16, 2007)

Hi,
Just installed new water heating system at home. Plumber who install radiators told me that i must insulate pex pipes in crawling space for heat loss reasons. This crawling space not cold in a winter time (about 50 F), but he told me i Must do it right with the fiberglass insulation (cost $6 for 6') , not with polyethylene foam pipe insulation ( cost $1 for 6' at HD). Guy who install boiler (25 years in heating business) told me polyethylene foam pipe insulation is OK and he use it all the time. I need to insulate 300' of the pex pipes and the price difference is hi! For whom I have to Trust? 

Thank you very much for your advices!


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## That one Guy (May 24, 2007)

He is correct about the heat loss. It happens here in the winter with copper pipe sometimes. It may not be always a noticable loss though. You should be fine with the foam pipe insulation. Cut the ends acordingly and tape them for an air tight seal. Fiberglass is great on some stuff but kinda old school.


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## kcrossley2 (Dec 17, 2006)

I'm interested in doing this too. Where's the best (most affordable) place online to buy foam pipe insulation?


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## BobVilla (Oct 15, 2008)

kcrossley2 said:


> I'm interested in doing this too. Where's the best (most affordable) place online to buy foam pipe insulation?


The best place I know online for pipe insulation is


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## tstorzuk (Jul 27, 2008)

You must NOT use polyethylene foam pipe insulation. It creats a reaction between the PEX and the insulation that degrades the PEX pipe.

Check with manufacturer of the PEX that you purchased. Some grades are able to be insulated with polyethylene foam pipe insulation. Most are not.


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## Alan (Apr 12, 2006)

Where's the documentation against using this type of insulation? Can you provide a link ? I'd really like to see it just for my own reference.

To the OP : The only problem I have with insulating pex is that you can't insulate the fittings very easily. That 1/2" insulation you get for the pipe won't go over the expanded joints. This might be different if you use the crimp rings instead, but I always hate insulating our pex jobs. :furious:


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## tstorzuk (Jul 27, 2008)

Alan,

I've been looking for that for a while this morning and I can't seem to find it.

If I recall correctly, it's in one of the following ASTM codes;

F876, F877, F1281, or F1960

Or it's on the manufacturer's web sites.

I can't find my copies of the ASTM codes, and therefore can't tell you exactly which one it's in. But I do remember it having to deal with the type of PEX pipe that is used. There are a few different ones;

PE-Xa, PE-Xb and PE-Xc.

I do not believe it was relevant to the PEX/Aluminum/Pex sandwich manufacturing method, as the aluminum acts like an insulating barrier already, and the reaction would probably be stopped by the aluminum and not carry though to the inner layer.

If you want to be sure, contact the manufacturer of the PEX that you have installed. That is what I did, and they told me NOT to use the polyethylene foam pipe insulation. Instead, I ran the PEX up in floor joists so that I could use standard fiberglass insulation in the areas where it ran.

I'm sorry, but if you're concerned about running $6 worth of materials as opposed to $1, I guess you're just worried about making a buck and turning the house to sale. If it's your home, then spend the extra $5, be sure about the safety of your piping system and sleep soundly.


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## Alan (Apr 12, 2006)

tstorzuk said:


> Alan,
> 
> I've been looking for that for a while this morning and I can't seem to find it.
> 
> ...


If you come across it in the future would you mind PMing it to me? I'd love to see it just for my own peace of mind


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## tstorzuk (Jul 27, 2008)

Alan,

I certainly will.

Right now I am in the process of emailing manufacturers to find out which ones shouldn't be insulated with that type. I've also asked for documentation, so I'll send it along and post it here when I get any replies.


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## Rory Read (Feb 9, 2010)

*insulating pex*

I insulate any pipe in an unconditioned space because I don't want it to freeze. I separately insulate hot water supply lines in conditioned spaces because I want to use less energy and deliver hotter water to the plumbing fixture or radiant loop. 

I have always used foam pipe wraps on Pex. I would be worried after reading this thread but for the fact that all my plumbers insulate it the same way. (I think it might just be some cpvc that you don't want to wrap with foam insulation sleeves, but that's a just a foggy and probably inaccurate memory. And by the way, if there is a problem with wrapping pex pipe with foam sleeves, I need to know too, although I really don't want to know.)

I insulate crawlspaces for all the reasons I insulate any other building exterior, and the why, how, and how much $ varies a bit case to case.

Thanks,

Rory

RDG Read Development LLC
Portland, OR


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## tstorzuk (Jul 27, 2008)

So what I have now found is contradictory to what was previously available. Attached is a service bulletin from one manufacturer that states the same. Also, an email that I have just received from a different manufacturer below;

Hello tstorzuk, 

Our Tubolit Polyethylene Pipe Insulation and AP Armaflex tubes do not have any adverse effects on any plumbing piping. At times, questions have been asked concerning our Armaflex 520 adhesive. 520 is a solvent based adhesive for sealing joints on the insulation. The 520 adhesive is also safe to use with PEX tubing. Armacell has performed numerous tests and our products are safe and recommended to use with PEX.

I believe the temperature limitations for PEX is 180 degrees F. We recommend our Tubolit Polyethylene Pipe Insulation also to 180 F. With a maximum temperature of 200 F. Polyethylene Pipe Insulation can melt if subjected to temperatures over 207 F.

Thank you, 
Bob Dizel
Armacell LLC
Sales & Marketing Manager, NorthEast


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## Daniel Holzman (Mar 10, 2009)

I cannot understand the chemistry behind a claim that polyethylene tubing (PEX) would react negatively with polyethylene foam insulation. Both products are made of polymerized ethylene (polyethylene). Polyethylene is well known for its chemical inertness, i.e. it is very difficult to get anything to bond to polyethylene because of the difficulty in achieving surface activation of the material. I cannot understand how polyethylene foam insulation could possibly react with PEX pipe, I too would be very interested in the documentation for this claim, and by the way my PEX pipe at home is insulated with polyethylene foam and if there is some history of trouble I certainly would like to know about it.


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## kcrossley2 (Dec 17, 2006)

If anyone decides to insulate their PEX, please post a few photos and a link to the product you used. Thanks!


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## vernon h (Mar 30, 2011)

I just ran pex in my attic insulated in the poly insulation. I just wonder to what temp it would protect it from freezing


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## Jim the plumber (May 16, 2011)

I was fixin to run pex under my house, there is no room to crawl under this house. It was built in the 20's and there is only about 5 or 6 inches of crawl space. there is concrete beams running 4' apart the length of the house with the floor joist resting on them. The crawl space is the space above the concrete beams and the floor so I cant dig.. I was going to run the pex across the beams, now I've read that pex needs to be clamped to a floor joist every couple of feet and theres no way I can do that. My plan was to just let it lay on the concrete beams. I was also going to use the polyethylene foam pipe insulation. I'm not really a plumber but I'm becoming one because no plumber here will touch this old house unless it's something inside, I live in Diamond back country and they're almost thicker than flies here.. Is there a reason I can't go ahead and let the pex lay on the beams without support, thats the way the galvanized pipe was installed that the pex will replace.


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## BOUTYM (Jun 30, 2006)

The only reason to secure PEX is to keep it from moving around and to keep it organized. Laying on concrete I could see it over time possibly chafing and ultimately failing because it is going to move around as a result of the water traveling through it and expansion/contraction. Movement would be especially prevalent where it changes direction.

What you might consider is laying down some 2x6 or 2x8 on the concrete depending on the number of lines you're running and securing the tubing to them every couple of feet, again paying particular attention to securing at changes in direction.


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## s_mack (Oct 16, 2011)

Hi. A little off topic and perhaps a bit basic...

I found this thread via Google. I'm frustrated with my new home and how bloody long it takes to get hot water to any of my taps. The single hot water tank is very central and it doesn't appear that any of the runs are that long - unless they've taken extremely inefficient runs to get there. House is mostly finished but there are some exposed pipes in the mechanical room/closet where the HWT is as well as one unfinished room that at least some of the pipes go through. Those areas themselves are indoor spaces and are not cold.

My question: Can I expect any benefit at all from adding pipe insulation to the few feet of exposed pipe that I can see? I'm not interested in tearing down drywall to add more. 

Thanks.

- Steven


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## BOUTYM (Jun 30, 2006)

s_mack said:


> Hi. A little off topic and perhaps a bit basic...
> 
> I found this thread via Google. I'm frustrated with my new home and how bloody long it takes to get hot water to any of my taps. The single hot water tank is very central and it doesn't appear that any of the runs are that long - unless they've taken extremely inefficient runs to get there. House is mostly finished but there are some exposed pipes in the mechanical room/closet where the HWT is as well as one unfinished room that at least some of the pipes go through. Those areas themselves are indoor spaces and are not cold.
> 
> ...


What's a 'few' feet? If you are literally talking a few feet it's probably not going to do much to insulation that with the exception that the insulation would help prevent condensation on the cold water pipe if humid air got to it, but I think there may be more to this.

When you say it takes a long time, how long are you talking? How hot is the water when it finally gets to the faucet? What is the temp set at on the water heater? Even though the heater is centrally located, how far is it from the faucets? What diameter pipe was used? Does the piping run from the heater below the floor and up to the fixtures? Are you building the house, or is it being built? Is insulation required in your area by code? Quite a few things figure into this.


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## s_mack (Oct 16, 2011)

Thanks for your reply. I don't have all the answers, but here are a few:

The house is already built and finished. I didn't build it... I just bought it.
The O.D. appears to be slightly larger than 3/4". No idea what the I.D. is.
A "few feet" isn't literally a few. All told, its about 26' but that's accounting for several runs or "branches" (sorry, I'm not a plumber and don't know the correct terms) to the various fixtures. As a general estimate, I'd figure its about 15% to 20% (give or take) of each run.
The kitchen sink is the one that annoys me the most because I use it to the most... it takes about 30 seconds to run hot. OK, that may not sound like a lot, but that's a lot of wasted water and I've never had a home take that long (although this is by far the largest home I've ever lived in). That's not the longest though... the main bathroom sink takes about 45 seconds and its probably the CLOSEST (in terms of physical straight line distance) to the tank.
When the hot water finally gets there... it is hot. I haven't taken a temperature, but it is sufficiently hot that you wouldn't want your hand in it for more than a couple of seconds.
I don't know what the tank is set to. I had a guy come and look at it and he turned it up arbitrarily to see if that helped... it didn't. The water is hotter now, but that wasn't the problem.
Physical straight line distance to the kitchen sink... it is 28 feet, but one floor up. However I have no idea at all what path it actually takes. The main bathroom is directly above the tank and that one takes the longest to heat up.
Yes, the tank is on the lower floor and it runs up to the fixtures above. Even for the lower floor fixtures, it appears the lines run up to the ceiling and over. They're no faster.
Is insulation required by our code? I imagine not. These are new homes... I would assume they meet code (but maybe that's asking too much).
I've considered a recirculating pump, but I really don't like the idea of the extra electricity and gas required to keep that going. But I also don't like wasting all the water while I wait for it to heat up! Plus I imagine I'm wasting gas anyway heating the water that goes into the pipes only to have them cool down.

- Steven


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## Thurman (Feb 9, 2009)

Having worked with PEX for some time now, I would not recommend just "laying" PEX on any substance. I firmly believe that just laying PEX on any surface will lead to a hole being rubbed into the PEX in due time. Notice how the pictures in your house seem to become slightly crooked over time? This is due to gravitational pull and I firmly believe the same effect will cause PEX to move slightly if just laid on some surface.


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## AlbacoreShuffle (Sep 18, 2011)

s_mack said:


> Thanks for your reply. I don't have all the answers, but here are a few:
> 
> The house is already built and finished. I didn't build it... I just bought it.
> The O.D. appears to be slightly larger than 3/4". No idea what the I.D. is.
> ...


I would install a Grundfo Comfort system.
They are very easy to install, and wont set you back to much $$$$

http://www.google.com/products/cata...a=X&ei=1gCbTs3tLIGfsQKrrZzhDA&ved=0CF0Q8wIwAA#


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## Daniel Holzman (Mar 10, 2009)

PEX moves very slightly if it is not secured. This has nothing to do with gravitational pull, which is downward, and cannot exert a lateral force on the pipe. The effect is due to temperature changes, which are particularly apparent on the hot water pipe, as the water in the pipe cools slowly if the water is not run, then heats up when a hot water tap is opened. PEX expands and contracts slightly with temperature change, leading to movement of the pipe.

The pipe also moves slightly due to forces exerted by flowing water around bends. There are loads exerted at bends when the water is flowing that must be resisted by the pipe itself if the pipe is not connected to the floor, and this leads to movement of the pipe as the water is turned on and off.

The movement is small, and if the pipe is not connected to the surface, there is little vertical load on the pipe, hence little friction. My guess is you could go 50 years without rubbing a hole in the pipe, however if the concrete is rough, and you want to protect the pipe, you can lay the pipe over a smooth surface like nylon or vinyl, a simple roll of 6 mil polyethylene would be fine. Then when the pipe moves, you will not wear out the pipe at all.


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## BOUTYM (Jun 30, 2006)

I've never really considered it until reading this thread, but is there any info or does someone know how much of a difference there is in heat loss with PEX vs. copper?


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## DIY4WIFE (Dec 29, 2008)

*Grundfos comfort system*

I'd rethink putting in that Grundfos system unless you don't have a problem with extra load on your water heater when cold water is used. Look up "hot water siphoning+hot water circulator". Saved me from cold water waiting and high gas bills.

I think there would be greater heat loss with copper since the metal absorbs heat quickly and it would allow heat to transfer to the outside surface of the pipe quicker.


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## goosebarry (Mar 28, 2012)

*Use insulation to reduce wear*



Jim the plumber said:


> I was fixin to run pex under my house, there is no room to crawl under this house. It was built in the 20's and there is only about 5 or 6 inches of crawl space. there is concrete beams running 4' apart the length of the house with the floor joist resting on them. The crawl space is the space above the concrete beams and the floor so I cant dig.. I was going to run the pex across the beams, now I've read that pex needs to be clamped to a floor joist every couple of feet and theres no way I can do that. My plan was to just let it lay on the concrete beams. I was also going to use the polyethylene foam pipe insulation. I'm not really a plumber but I'm becoming one because no plumber here will touch this old house unless it's something inside, I live in Diamond back country and they're almost thicker than flies here.. Is there a reason I can't go ahead and let the pex lay on the beams without support, thats the way the galvanized pipe was installed that the pex will replace.


Getting back on topic. 
As mentioned PEX pipe moves around if not secured and can eventually wear through. Why don't you kill two birds with one stone and insulate the pipe with the foam pipe before you place it over the concrete. This will give you an extra thick wear layer. I would probably wrap it in duct tape (cheap solution) or run it through the corrugated pipe used for underground PEX to give it a little more protection.
You probably should get your plumbing inspectors opinion on this.


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## goosebarry (Mar 28, 2012)

*Hanging Insulated PEX pipes*

I plan on insulating a 30 foot straight run of PEX pipe running through the basement perpendicular to the joists. If I mount the pipe to the joist using talons or clips before I insulate the pipe, I'll have to notch around all the joists. So I was thinking of insulating the pipe first, but now I need some oversized hangers to hang the insulated pipe.

Does anyone have any suggestions?


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## Homerepairguy (Aug 1, 2010)

Jim the plumber said:


> I was fixin to run pex under my house, there is no room to crawl under this house. It was built in the 20's and there is only about 5 or 6 inches of crawl space. there is concrete beams running 4' apart the length of the house with the floor joist resting on them. The crawl space is the space above the concrete beams and the floor so I cant dig.. I was going to run the pex across the beams, now I've read that pex needs to be clamped to a floor joist every couple of feet and theres no way I can do that. My plan was to just let it lay on the concrete beams. I was also going to use the polyethylene foam pipe insulation. I'm not really a plumber but I'm becoming one because no plumber here will touch this old house unless it's something inside, I live in Diamond back country and they're almost thicker than flies here.. Is there a reason I can't go ahead and let the pex lay on the beams without support, thats the way the galvanized pipe was installed that the pex will replace.


Jim,

Can you push PVC pipe over the concrete beams? If so, you could install PVC pipes larger than the PEX lines and then push or pull the PEX lines through them. This would solve the distance between clamps and the abrasion problems.

If you do this, I recommend installing a 360 degree loop in the PEX lines at both ends, but if not possible, at least at one end. The loop will allow the PEX to expand and contract properly. It is especially imperative that the 360 degree loops at the ends be installed for the hot water line. PEX hot water lines expand and contract quite a bit and installed in PVC pipes, there will not be the droop between hangers to help absorb that movement.

I would install one 360 degree loop at one end for cold water lines and two 360 degree loops at both ends for hot water lines (though one larger 360 degree loop for a hot water line could work too).

HRG


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## VIPlumber (Aug 2, 2010)

goosebarry said:


> I plan on insulating a 30 foot straight run of PEX pipe running through the basement perpendicular to the joists. If I mount the pipe to the joist using talons or clips before I insulate the pipe, I'll have to notch around all the joists. So I was thinking of insulating the pipe first, but now I need some oversized hangers to hang the insulated pipe.
> 
> Does anyone have any suggestions?


I use EMT 2 hole clamps. They work great over insulated pipe.


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## goosebarry (Mar 28, 2012)

The 2" 2 hole EMT clamp is perfect. The local store had 2" 1 hole EMT and 2" 2 hole PVC. The pipe with insulation is a little loose in the PVC clamp. The EMT clamp can be deformed a little to better hold the insulation. One screw hole isn't secure enough around this klutz. I could see me pulling down 50 feet of pipe. I need 2 holes. :laughing:

Thank you


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