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Best Insulated Pex

Qfe Member Posts: 1
I'm getting ready to

install a new Outdoor Wood Boiler and need 1 1/4" insulated pipe to feed

the existing system in the house.  Looking through the internet there are

several types of pre-insulated pex (PIP) piping but very limited data on several. 

I’m looking for something with good thermal characteristics (low heat loss)

that won’t cost a fortune.

What are your experiences with the different brands of PIP? 

Are there any brands to stay away from? 

Is there a best brand of  pre-insulated pex piping? 

What’s the most cost-effective?


Thank you for your help.


  • Mark Eatherton
    Mark Eatherton Member Posts: 5,853

    Cost effective....

    If you go with the least expensive first cost, and it falls apart 5 years down the road, and you end up having to dig up the yard and replace it again, WAS it cost effective?

    I find that if I am going to have to bury ANYTHING, I want the highest quality product I can get, because quite frankly, I hate digging, unless I am in my own garden...

    I have used ECOFLEX. It's not cheap, but it is good. THe fittings get pricey, but they don't leak. All of them are real hard to work with (2 to 3 people to get it done right) because of its strong memory.

    It's not so much a case of "You got what you paid for", as it is a matter of "You DIDN'T get what you DIDN'T pay for, and you're NOT going to get what you thought you were in the way of comfort". Borrowed from Heatboy.
  • hot_rod
    hot_rod Member Posts: 21,844

    be sure you check the flow rate thru the tube. 1-1/4"  Pex with insert fittings will not flow the same as copper or steel pipe of that size.  The most common mistake is undersizing the lines from the units, then trying to over come that with high head circs.  The tube manufacturers should have flow charts for their various sizes.

    I suppose it depends on your location, bury depth, frost levels, etc.  If it can expect to see freezing conditions that is a huge delta T.  180F or higher fluid in the pipe, 32F around presents a lot of loss potential.

    I'm not convinced any of the pre-insulated products have adequate insulation.  Seems 1/2- 3/4' at the thinnest spot? 

     Some installers foam over the pre-insulated pex with spray foam.  Or lay a strip of foamboard down in the trench first,over a gravel drainage layer, the pex, then have it all spray foamed.

    The bigger concern is water in the trench.  Do all you can to assure the tube in never in standing or running water. You don't want surface or ground water around the insulated tube. The outer jacket needs to be 100% waterproof also, any cut or rip in the outer jacket would allow water in and cause serious heat loss.  Spend time on your plan, it's an expensive re-do.

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • zacmobile
    zacmobile Member Posts: 211
    insulated pex

    The last time I ran insulated pex I used Heat Seal By Heat Link, it's similar to Uponor's & Rehau too I think in that it's multilayered insulation which makes it super flexible compared to some of the fairly rigid spray foam type ones i've used in the past. Also, it has a double outer wall so puncturing is less of a worry. Ran about 100ft of dual 1" and about 1 deg loss at the receiving end, not bad I think.

  • Solid_Fuel_Man
    Solid_Fuel_Man Member Posts: 2,646
    Visit the Hearth

    If you've never been to Hearth.com you should take a visit.  Click on the forums icon, and then "the boiler room" it's a wealth of information on subjects just like this.  They are big on the foam in place method, with people trying all sorts of things only to find huge heat losses to the ground.  As mentioned KEEP IT DRY!

    Serving Northern Maine HVAC & Controls. I burn wood, it smells good!
This discussion has been closed.