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Community and Q&A

In regards to the post by Martin on how cold effects R-5 XPS vs R-6 PolyIso.

Irishjake | Posted in GBA Pro Help on

I have included a link to a German Study on the effects of cold/heat/moisture on various types of insulation – it seems to state that all insulation suffers degradation at colder temps – which is obviously not what your study points too. Could you possibly elaborate more on this? Am I wrong to read the results the way I have? If not why the difference in outcomes?

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  1. GBA Editor
    Martin Holladay | | #1

    Look at the graphs again: at colder temperatures, the conductivity of most types of insulation goes down -- which means that the insulation materials are more effective, not less effective.

    Conductivity may be good if you are designing electrical wiring, but it is bad if you are designing an insulation system.


  2. Irishjake | | #2

    Yeah I forgot that is the inverse of K to figure the R value!

  3. jinmtvt | | #3

    Just were do you see measurement on PolyIso in that link ? i see none ...

    Funny how the XPS r value is lower than that of the EPS.

  4. Expert Member
    Dana Dorsett | | #4

    Jin: The XPS in Europe is usually blown with CO2, and has a lower R-value than XPS blown with HFCs. I'm not sure if European EPS is blown with pentane or something else. The also don't specifity the density of he samples tested. Both the density and blowing agents will make a difference.

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