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Fiberglass Batts- <br /> ,, Labeled vs. Installed Performance <br /> Summary: Oak Ridge National Laboratory research shows that "perfectly installed" baits <br /> lose 11% of their labeled R-Value, and that "commonly installed"fiberglass batts <br /> lose 28% of their labeled R-value) <br /> This study confirms tests conducted 20 years ago by fiberglass manufacturers, and <br /> reveals the surprisingly large disparity between the labeled R-value and the <br /> installed R-value of fiberglass bans.' <br /> "R-19"baits have an R- <br /> value of 13.7 when <br /> Who: Oak Ridge National Laboratory 3 installed as commonly <br /> found in actual walls. 9 <br /> What Was The R-value results presented here are the clear <br /> Measured: wall R-values, which Andre Desjarlais of Oak <br /> Ridge explains,"includes the studs,top and <br /> bottom plates,sheathings and exterior facade... <br /> It does not include additional structural r' <br /> components around details such as corners, <br /> windows,etc."4 <br /> "The clear wall R-value... represents the area ° <br /> of the wall containing insulation and only the <br /> necessary structural member away from all Figure 1—Full size 8'x 8'wall sections were <br /> interface details."5 built using 2 x 6 wood framing 24"o.c. <br /> (Note that 89%of the surface area of the wall is <br /> insulated with"R-19"labeled bans and just <br /> Why: "To address the number one wall research 11%is wood framing.) <br /> need...whole wall performance was ranked by <br /> 270 private building industry contributors as <br /> the most important public sector R&D need to s-„c.°amH aosa Weiw,w.o <br /> accelerate the development and application of ��_ <br /> energy-efficient building walls."6 von laa1 •;.�� <br /> lation <br /> How: Full-size walls were constructed and tested to <br /> inc <br /> airs <br /> determine their thermal conductivity.' "' °gypsum°°°"l <br /> What Did The highest tested R-value for"R-I9"labeled : x4-.amr„m,. 1 <br /> They Find: batts was R-17.4 for batts before they were Figure 2—The 2"x 6"wood framed wall was <br /> installed. From there,the test results dropped to insulated with"R-19"labeled fiberglass batts <br /> R-17 and then R-13.7 B and enclosed with 5/8 inch exterior OSB <br /> sheathing and 1/2 inch gypsum board. <br />