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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='color:#1F497D'>Hi James,<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>As you said, Window5 does offer a default value for Thermally Broken AL (U-1.0 BTU/h∙ft∙F). I’ve seen some thermally broken frames with much worse performance (U-1.5). I’m currently looking at modeling a YKK frame right now with our glass, and the frame performance is around U-0.9. I haven’t seen anything near U-0.5.<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>I believe that the U-value of the frame will vary based on the glass package that it is modeled with, but I’m not sure by how much.<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>I know SeriousMaterials now has a fiberglass framed window that are Heavy Commercial (CW) rated - <a href="http://www.seriouswindows.com/commercial/products/heavy-commercial.html">link</a>. Fiberglass has comparable thermal properties to wood and vinyl – I believe these windows have as high as U-0.19 (frame+glass performance). The frame conductance is around U-0.5.<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>Although I think using THERM is a good approach (I just learned how using this 17 minute video by LBNL - <a href="http://windows.lbl.gov/software/therm/demo/Sample/index.html">link</a>) you can create a new generic frame material in WINDOW5 and assign the frame conductivity. I would say U-0.8 or 0.9 is the best you’ll do with thermally broken AL and U-0.5 is where fiberglass is.<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>Regards,<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>Alex Krickx<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;color:#262F13'>Alex Krickx, LEED AP<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:9.0pt;color:gray'>Building Energy Specialist<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:8.0pt;color:#1F497D'><img border=0 width=121 height=42 id="Picture_x0020_1" src="cid:image001.jpg@01CBD808.4C57C6B0" alt="email_sig"></span><span style='color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:9.0pt;color:#1F497D'>1250 Elko Dr, Sunnyvale, CA 94089<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:9.0pt;color:#1F497D'>(t) 408.541.8124<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:9.0pt;color:gray'><o:p> </o:p></span></p><p class=MsoNormal><b><i><span style='font-size:7.5pt;font-family:"Arial","sans-serif";color:#1F497D'>Warning:</span></i></b><i><span style='font-size:7.5pt;font-family:"Arial","sans-serif";color:#1F497D'> The information contained in this e-mail may be privileged attorney-client communications or attorney work product and/or proprietary and confidential. If the reader of this message is not the intended recipient then you have received it in error and any review, distribution or copying of this message is prohibited and you are to notify us immediately by reply e-mail and delete the original message immediately.</span></i><span style='color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><div><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> bldg-sim-bounces@lists.onebuilding.org [mailto:bldg-sim-bounces@lists.onebuilding.org] <b>On Behalf Of </b>James Hansen<br><b>Sent:</b> Tuesday, March 01, 2011 9:46 AM<br><b>To:</b> bldg-sim@lists.onebuilding.org<br><b>Subject:</b> [Bldg-sim] aluminum window frame U-values<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I was wondering if anyone would be willing to share thermally broken aluminum frame conductance values that they’ve been using in recent Windows5 center-of-glass calculations. I don’t have information on the particular aluminum frames for my current project, so I don’t really want to try and learn THERM quite yet.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Most of the older documentation online that I’ve found shows that thermally broken aluminum frames typically have a U-value of about 1.0. This jives with one of DOE-2s window entries for a PPG glass with a frame conductance of 0.94.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Almost every commercial building constructed these days is made with aluminum framed windows…I just have a hard time believing that manufacturers haven’t figured out better ways to insulate the frames. With vinyl and wood having U-values < 0.4, I have to think that aluminum frames should be able to at least approach 0.5, if not lower. Unfortunately not a lot of manufacturers of aluminum frames post their thermal characteristics.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>What are people using?<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Thanks in advance!<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><b><span style='font-family:"Arial","sans-serif";color:teal'>GHT Limited<br></span></b><b><span style='font-family:"Arial","sans-serif"'><ns0:PersonName><span style='color:black'>James Hansen</span></ns0:PersonName></span><span style='color:black'>, PE, LEED AP<o:p></o:p></span></b></p><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:black'>Senior Associate</span><span style='color:black'><o:p></o:p></span></b></p><p class=MsoNormal><span style='font-size:7.5pt;font-family:"Arial","sans-serif"'><ns0:Street><ns0:address><span style='color:black'>1010 N. 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