insulation or air filled

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vitorules
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Joined: Mon Jul 16, 2012 7:14 pm

insulation or air filled

#1 Post by vitorules »

Purchasing replacement double hung windows. getting conflicting opinions regarding whether the spaces inside the window frame should be air chambers or filled with insulation. Can anyone assist?

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Randy
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Joined: Fri Oct 08, 2004 7:26 am
Location: Houston, TX

Re: insulation or air filled

#2 Post by Randy »

Insulated frames are marginally better. Not enough of an improvement to be a deal killer though.

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HomeSealed
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Location: Milwaukee, Madison, SE Wisconsin

Re: insulation or air filled

#3 Post by HomeSealed »

+1. It helps in some windows more than others, my general rule of thumb is to look at how it effects the U-value. Some products improve by a couple points, others don't move at all. Ultimately, the performance ratings of the unit are what tell you how the will actually perform, so be careful not to get too hung-up on how it gets there. A window with a .28 u value and no foam will be a better performer than one at .30 that has foam.

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Windows on Washington
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Re: insulation or air filled

#4 Post by Windows on Washington »

I have seen the data both ways on different windows. It depends, in large part, on the construction of the window and if any of the outer chambers are thermally bridged to the interior.

If that condition exists, it can make a difference more pronounced.

I tend to look at the cost vs. the performance improvement. If the math makes sense, go for it.

masterext
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Re: insulation or air filled

#5 Post by masterext »

a foam filled extrusion usually adds 1-2 points on the total U-factor. since a windows efficiency is measured with both glass and frame, foam will add insulation value. also, from a structural standpoint, it also adds some rigidity as well as some noise reduction. personally, i lile it and think its a good idea. coincidentally, each of the top 5 window manufacturers offer a foam filled frame.
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