You want to keep the exhaust and fresh air intake runs short to minimize fan power and preferably out of the conditioned space as they will have air of (approx) outside temps. If you must run them long through conditioned space you'd want to insulate.<div>
<br></div><div><div>---- Steve (KZ6LSD)<br>
<br><br><div class="gmail_quote">On Thu, Nov 4, 2010 at 11:35 AM, elitalking <span dir="ltr"><<a href="mailto:elitalking@rockbridge.net">elitalking@rockbridge.net</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
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<p style="margin:0in 0in 0pt" class="MsoNormal"><span style="line-height:115%;font-family:'Times New Roman','serif';font-size:16pt">Thanks
for your input on HRV versus ERV.<span> </span>I
really enjoyed the discussion that followed concerning the health impact of
humidity.<span> </span>I gained new knowledge
from that series.<span> </span></span></p>
<p style="margin:0in 0in 0pt" class="MsoNormal"><span style="line-height:115%;font-family:'Times New Roman','serif';font-size:16pt"> </span></p>
<p style="margin:0in 0in 0pt" class="MsoNormal"><span style="line-height:115%;font-family:'Times New Roman','serif';color:black;font-size:16pt"><a title="steve@tjiang.org" href="mailto:steve@tjiang.org" target="_blank"><span style="color:black;text-decoration:none">Steven
Tjiang</span></a> writes:</span></p>
<p style="margin:0in 0in 0pt" class="MsoNormal"><span style="line-height:115%;font-family:'Times New Roman','serif';font-size:16pt">Your
analysis seem correct for your climate. If there is no active source of
moisture removal an ERV would only delay the inevitable equalization of humidity
between the external and the internal.</span></p>
<p style="margin:0in 0in 0pt" class="MsoNormal"><span style="line-height:115%;font-family:'Times New Roman','serif';font-size:16pt"> </span></p>
<p style="margin:0in 0in 0pt" class="MsoNormal"><span style="line-height:115%;font-family:'Times New Roman','serif';font-size:16pt">I
have decided to install ERV, even though I am not immediately planning to
install the active moisture removal to take advantage of the ERV’s ability to
preserve that value.<span> </span>I decided to
preserve the option of installing active moisture removal such as a mini-split
heat pump.<span> </span>Living in a wooded
location, with upgraded thermal efficiency from tighter and higher conductive
insulation, I have the potential for grid tied photovoltaic array in field where
there is full sunshine to produce the electricity credits in summer to pay for
heat in winter.<span>
</span></span></p>
<p style="margin:0in 0in 0pt" class="MsoNormal"><span style="line-height:115%;font-family:'Times New Roman','serif';font-size:16pt"> </span></p>
<p style="margin:0in 0in 0pt" class="MsoNormal"><span style="line-height:115%;font-family:'Times New Roman','serif';font-size:16pt">The
next issue what ERV to use. <span> </span>My
house is small.<span> </span>Using ASHRAE
formula for required ventilation = (.01cfm/sf x Area(sf)) + 7.5cfm/occupant x
#occupants), I only need 22cfm.<span>
</span></span></p>
<p style="margin:0in 0in 0pt" class="MsoNormal"><span style="line-height:115%;font-family:'Times New Roman','serif';font-size:16pt"> </span></p>
<p style="margin:0in 0in 0pt" class="MsoNormal"><span style="line-height:115%;font-family:'Times New Roman','serif';font-size:16pt">Is
there a source of information for comparing the performance of various
manufacturers and models?</span></p>
<p style="margin:0in 0in 0pt" class="MsoNormal"><span style="line-height:115%;font-family:'Times New Roman','serif';font-size:16pt"> </span></p>
<p style="margin:0in 0in 0pt" class="MsoNormal"><span style="line-height:115%;font-family:'Times New Roman','serif';font-size:16pt">Efficiency
of recovery and reliability are important factors.<span> </span>Rcomendations will be appreciated.<span> </span></span></p>
<p style="margin:0in 0in 0pt" class="MsoNormal"><span style="line-height:115%;font-family:'Times New Roman','serif';font-size:16pt"> </span></p>
<p style="margin:0in 0in 0pt" class="MsoNormal"><span style="line-height:115%;font-family:'Times New Roman','serif';font-size:16pt">I
am considering </span></p>
<p style="margin:0in 0in 0pt" class="MsoNormal"><span style="line-height:115%;font-family:'Times New Roman','serif';font-size:16pt">*
Fanteck <b>5504.153 </b>SE 704N Compact ERV</span></p>
<p style="margin:0in 0in 0pt" class="MsoNormal"><span style="line-height:115%;font-family:'Times New Roman','serif';font-size:16pt">*
Panasonic ERV FV-04VE1</span></p>
<p style="margin:0in 0in 0pt" class="MsoNormal"><span style="line-height:115%;font-family:'Times New Roman','serif';font-size:16pt">*
Renew air model to be determined.<span>
</span></span></p>
<p style="margin:0in 0in 0pt" class="MsoNormal"><span style="line-height:115%;font-family:'Times New Roman','serif';font-size:16pt"> </span></p>
<p style="margin:0in 0in 0pt" class="MsoNormal"><span style="line-height:115%;font-family:'Times New Roman','serif';font-size:16pt">I
spoke with an engineer recently that recommended Renew Air Energy Recovery Flat
Plate HX.<span> </span>He told me that some
ERV’s with desicant wheels have leakage between air flows and maintenance issues
caused by bearing and seal of wheel.<span>
</span>The ERV he recommended has some different method of transferring humidity
that flows over plates.<span>
</span></span></p>
<p style="margin:0in 0in 0pt" class="MsoNormal"><span style="line-height:115%;font-family:'Times New Roman','serif';font-size:16pt"> </span></p>
<p style="margin:0in 0in 0pt" class="MsoNormal"><span style="line-height:115%;font-family:'Times New Roman','serif';font-size:16pt">I
have an L shaped 36’x26’house with long leg 10’wide and short leg 24’wide.<span> </span>I am looking at installing HRV near
north wall in area common to both legs so a straight 4” duct can deliver fresh
air to opposite side of each leg.<span> </span>A
parallel duct on one of the legs would deliver exhaust air to South side for
plenty of separation between inlet and outlet.<span> </span>Is there a disadvantage for having the
exhaust duct going 20’ through conditioned space?<span> </span>Would it be advantage to have the long
leg be the outdoor air supply instead.<span>
</span>I could send exhaust air out North side near inlet, but then continue to
open end to achieve the separation needed instead of crossing the house.<span> </span>I would like to use PVC pipe to insure
tightness.<span>
</span></span></p></div></div>
</blockquote></div><br></div></div>