I believe RESNET allows for credit for infiltration reduction below 0.35 ACH for confirmed construction (blower door tested).<br><br>In my opinion, leaving out infiltration is a major fault of ASHRAE 90.1 and Appendix G (and LEED). Reducing infiltration through good building techniques and attention to detail can have an enormous impact on building energy use. Yes, the building must be tested in order to receive credit, but infiltration needs to be brought to the attention for designers and owners. Also, ensuring that the air barrier is OUTSIDE the insulation (not the interior sheetrock) is essential to ensuring the performance of the insulation.<br>
<br>I recently completed an evaluation for an existing historic building about to undergo renovations. The biggest single potential energy saver? Infiltration reduction. Will we get LEED credit for this? No.<br><br>~karen~<br>
<br><div class="gmail_quote">On Feb 13, 2008 11:17 AM, Michael Tillou <<a href="mailto:michael.tillou@gmail.com">michael.tillou@gmail.com</a>> wrote:<br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
Nick,<br><br>ASHRAE 90.1 doesn't allow any credit for infiltration savings for commercial<br>buildings and doesn't have any specific guidance about an allowable air<br>tightness value. When using Appendix G or Chapter 11 ECB you need to keep<br>
infiltration the same in both the proposed design and the energy budget.<br><br>The IECC and RESNET HERS offer a method for infiltration savings in<br>Low-Rise/Single Family Residential. I believe both methods allow a minimum<br>
as-designed infiltration of ACH = 0.35. The baseline uses weather factors<br>from ASHRAE 136 and a Normalized Leakage value of 0.57. The IECC also<br>requires a post-construction blower door test to verify the savings.<br>
<br>You could probably propose an exception calculation for infiltration credit<br>if it followed the IECC residential method and the proposed building was a<br>small building with simple systems. I certianly don't think it would be<br>
applicable for a large multi-story building with complex systems. I think<br>that you would also need to be able to demonstrate the as-built (post<br>construction) infiltration rate, through blower door testing or other<br>
appropriate means, as part of proposed exception calculation.<br><br>Best regards,<br><br>Mike<br><div class="Ih2E3d"><br><br><br>-----Original Message-----<br>From: <a href="mailto:bldg-sim-bounces@lists.onebuilding.org">bldg-sim-bounces@lists.onebuilding.org</a><br>
[mailto:<a href="mailto:bldg-sim-bounces@lists.onebuilding.org">bldg-sim-bounces@lists.onebuilding.org</a>] On Behalf Of Nick Doylend<br>Sent: Tuesday, February 12, 2008 3:58 PM<br>To: <a href="mailto:bldg-sim@lists.onebuilding.org">bldg-sim@lists.onebuilding.org</a><br>
Subject: [Bldg-sim] 90.1 and infiltration/air-tightness?<br><br></div><div><div></div><div class="Wj3C7c">Hi, I'm wondering if 90.1 makes any stipulations regarding building air<br>infiltration, for example can there be a difference between proposed design<br>
and energy budget building? I can't seem to find any reference to facade<br>air tightness but the standard is a pretty dense document to wade though.<br>Is there a more easily digested summary available anywhere?<br>
<br>Thanks,<br><br>Nick<br>_______________________________________________<br>Bldg-sim mailing list<br><a href="http://lists.onebuilding.org/listinfo.cgi/bldg-sim-onebuilding.org" target="_blank">http://lists.onebuilding.org/listinfo.cgi/bldg-sim-onebuilding.org</a><br>
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