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</o:shapelayout></xml><![endif]--></head><body lang=EN-CA link=blue vlink=purple><div class=WordSection1><p class=MsoNormal>Dear Friends<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>There is a brief discussion of the R-value used to report building insulation metrics at <a href="http://www.greenbuildingadvisor.com/blogs/dept/musings/bold-attempt-slay-r-value?lookup=auto&V27=&V28=&V29=&V30=&V31=&V32=&V33=&V34=&V35=&V55=&V56=&Taun_Per_Flag=true&utm_source=email&utm_medium=eletter&utm_content=20110829-r-value-obsolete&utm_campaign=fine-homebuilding">http://www.greenbuildingadvisor.com/blogs/dept/musings/bold-attempt-slay-r-value?lookup=auto&V27=&V28=&V29=&V30=&V31=&V32=&V33=&V34=&V35=&V55=&V56=&Taun_Per_Flag=true&utm_source=email&utm_medium=eletter&utm_content=20110829-r-value-obsolete&utm_campaign=fine-homebuilding</a><o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>The main point is that the insulation value of materials changes with temperature and how it is applied. <o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>One proposal is that a heterogeneous test report (a set of charted curves reflecting performance under different conditions) be used instead of a single R-value. (R is the inverse of the U value, or thermal conductance).<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><span lang=EN>“R-value took us a long way down the path,” Lstiburek said. “Fifty years is a long time.”<o:p></o:p></span></p><p class=MsoNormal><span lang=EN><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN>In the same vein, I advocate the use of stove performance tests and performance reporting reflecting how the stove works under different conditions, primarily different pot sizes, different power levels and different fuel moisture levels.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN>Presented with a chart of performance curves for different stoves, the buyer can select the one that performs best by matching the offerings to their fuel type(s) and cooking or heating needs. Fortunately it is much easier to test stoves heterogeneously than a building (read the article!).<o:p></o:p></span></p><p class=MsoNormal><span lang=EN><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN>Regards<o:p></o:p></span></p><p class=MsoNormal><span lang=EN>Crispin<o:p></o:p></span></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><span style='font-size:8.0pt;font-family:"Garamond","serif";color:black;mso-fareast-language:EN-CA'><o:p> </o:p></span></p><p class=MsoNormal><o:p> </o:p></p></div></body></html>