<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Dear Derek and everyone<div><br></div><div>As I see it Passiv Haus presents one of the biggest challenges to the Natural Building movement for many years </div><div>In the Uk , the AECB (<a href="http://www.aecb.net">http://www.aecb.net</a>) used to be a good advocate for low impact building but now it has sold its soul to Passiv Haus and seems to have reverted to the "Only energy in use argument"</div><div>There are of course a number of passiv haus projects that have used low embodied energy materials ( particularly in Austria) but most do not </div><div>I have challenged the leading figures of the Passiv Haus movement face to face to justify why they exclude considerations of embodied energy but their answer is to say that you can meet their standards with natural materials. So why not advocate the use of natural materials then?</div><div>Many of the Passiv haus approved windows are made from uPVC</div><div><br></div><div>I think it is very hard to justify a dependence on mechanical ventilation to get fresh air into buildings.</div><div>The achilles heel of MVHR systems is changing the filters</div><div><br></div><div>Fundamentally passiv haus presents a philosophy that buildings can only be low energy if they use expensive high tech equipment</div><div>In the UK and Ireland a passiv haus costs between 50 and 100% more than a conventional low energy house</div><div><br></div><div>Personally I prefer the Walter Segal philosophy of putting on another jumper rather than sealing myself up with a lot of plastic and toxic materials.</div><div><br></div><div>I will be in Darmstadt in November and am considering mounting a picket of the Passiv Haus HQ for an hour or two</div><div>Anyone want to join me??</div><div><br></div><div>Tom</div><div><br></div><div><br><div><div>On 19 Oct 2011, at 02:25, Derek Roff wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div><div>On Oct 18, 2011, at 4:46 PM, Graeme North wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><span class="Apple-style-span" style="border-collapse: separate; font-family: Helvetica; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; font-size: medium; ">I also question (<i>and here I risk swearing in church</i>) the whole philosophy of tightly sealed "passiv haus" which are then mechanically ventilated. The energy intensive approach this embodies is also up there at the doubtful end of the spectrum it seems to me. Great until the power goes out. </span></blockquote></div><div><br></div>As John Straube has delineated in a number of places, the "passiv haus" standards for air sealing are neither science based, nor completely in harmony with other passiv haus goals. That being said, this doesn't eliminate the value of mechanical ventilation in many climates and situations. It should be a net energy-saving feature, rather than an energy consuming one. <br><div> <span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; font-size: medium; "><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; font-size: medium; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div><br class="Apple-interchange-newline">Derek Roff</div><div><a href="mailto:derek@unm.edu">derek@unm.edu</a></div><div><br></div></div></span><br class="Apple-interchange-newline"></span><br class="Apple-interchange-newline"> </div> <br></div>_______________________________________________<br>GSBN mailing list<br><a href="mailto:GSBN@sustainablesources.com">GSBN@sustainablesources.com</a><br>http://sustainablesources.com/mailman/listinfo.cgi/GSBN<br></blockquote></div><br><div apple-content-edited="true"> <span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-size: medium; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><span class="Apple-style-span" style="border-collapse: separate; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; -webkit-text-decorations-in-effect: none; text-indent: 0px; -webkit-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><span class="Apple-style-span" style="border-collapse: separate; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; -webkit-text-decorations-in-effect: none; text-indent: 0px; -webkit-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "><span class="Apple-style-span" style="border-collapse: separate; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; -webkit-text-decorations-in-effect: none; text-indent: 0px; -webkit-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "><div>Tom Woolley</div><div><br class="khtml-block-placeholder"></div><div>Rachel Bevan Architects</div><div>80 Church Road</div><div>Crossgar</div><div>Downpatrick</div><div>BT30 9HR</div><div><a href="mailto:tom.woolley@btconnect.com">tom.woolley@btconnect.com</a></div><div>028 44 830988</div><div><a href="http://www.bevanarchitects.com">www.bevanarchitects.com</a></div><br class="Apple-interchange-newline"></span></span></div></span></div></span><br class="Apple-interchange-newline"> </div><br></div></body></html>