<html><head></head><body text="#000000" bgcolor="#FFFFFF" data-blackberry-caret-color="#00a8df" style="background-color: rgb(255, 255, 255); line-height: initial;"><div id="BB10_response_div" style="width: 100%; font-size: initial; font-family: Calibri, 'Slate Pro', sans-serif; color: rgb(31, 73, 125); text-align: initial; background-color: rgb(255, 255, 255);">Biggest emerging issue (pun intended) is rising grounwater</div> <div id="response_div_spacer" style="width: 100%; font-size: initial; font-family: Calibri, 'Slate Pro', sans-serif; color: rgb(31, 73, 125); text-align: initial; background-color: rgb(255, 255, 255);"><br style="display:initial"></div> <div id="_signaturePlaceholder" style="font-size: initial; font-family: Calibri, 'Slate Pro', sans-serif; color: rgb(31, 73, 125); text-align: initial; background-color: rgb(255, 255, 255);">Sent from my BlackBerry 10 smartphone on the Rogers network.</div> <table width="100%" style="background-color:white;border-spacing:0px;"> <tbody><tr><td id="_persistentHeaderContainer" colspan="2" style="font-size: initial; text-align: initial; background-color: rgb(255, 255, 255);"> <div id="_persistentHeader" style="border-style: solid none none; border-top-color: rgb(181, 196, 223); border-top-width: 1pt; padding: 3pt 0in 0in; font-family: Tahoma, 'BB Alpha Sans', 'Slate Pro'; font-size: 10pt;"> <div><b>From: </b>Topher</div><div><b>Sent: </b>Wednesday, August 21, 2013 09:48</div><div><b>To: </b>Green Building</div><div><b>Reply To: </b>topher@greenfret.com</div><div><b>Subject: </b>Re: [Greenbuilding] passive haus article</div></div></td></tr></tbody></table><div id="_persistentHeaderEnd" style="border-style: solid none none; border-top-color: rgb(186, 188, 209); border-top-width: 1pt; font-size: initial; text-align: initial; background-color: rgb(255, 255, 255);"></div><br><div id="_originalContent" style="background-color: rgb(255, 255, 255);">
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<div class="moz-cite-prefix">On 8/21/2013 8:50 AM, John F Straube
wrote:<br>
</div>
<blockquote cite="mid:9A6592BF-9633-432D-980E-C62BD701FDF7@uwaterloo.ca" type="cite">Heat loss through the slab is the same as heat loss
through an airtight wall. If someone told you that the physics
are different they are not.</blockquote>
<br>
Well, Physics is the same pretty much everywhere except an extremely
deep gravity well. But we don't calculate heat loss from elementary
physics. Certainly the calculation for heat loss is done
differently between walls and slabs. I do agree that the
distinction between convective and conductive losses is not that
simple.<br>
<br>
<blockquote cite="mid:9A6592BF-9633-432D-980E-C62BD701FDF7@uwaterloo.ca" type="cite">I recoil at the notion of large amounts of insulation
(even 4" of foam is a lot) under the slab because it does not save
much energy, unless you use some weird energy model that does not
relate to measured sub- slab conditions. </blockquote>
<br>
Being pedantic, I would claim that the energy saved depends not at
all on <i>any</i> energy model, but rather on reality. But I am
curious what you would classify as a 'weird energy model'. I would
also caution readers, as always, that the climates and soil
conditions vary; blanket assertions are almost always wrong in SOME
situation. We certainly don't get 55°F slabs around here.<br>
<br>
Thank You Kindly,<br>
<br>
Corwyn / Topher Belknap<br>
<pre class="moz-signature" cols="72">--
Topher Belknap
Green Fret Consulting
Kermit didn't know the half of it...
<a class="moz-txt-link-freetext" href="http://www.GreenFret.com/">http://www.GreenFret.com/</a>
<a class="moz-txt-link-abbreviated" href="mailto:topher@greenfret.com">topher@greenfret.com</a>
</pre>
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