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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D">Hi Tedd,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D">Thanks for your input. You raise a good point about the wind pressure from the local microclimate - something to consider.<o:p></o:p></span></p>
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color:#1F497D"> <o:p></o:p></span></p>
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color:#1F497D">Since ASHRAE 62.2 is trying to prevent to under-the-door infiltration of air quality issues you mention, and if the units have their own make-up air supply
you could probably use door sweeps. You're right - either the bath fan or the stove hood exhaust alone could ventilate the unit in exhaust-only mode, so the question then becomes where to get the make-up air supply?
<o:p></o:p></span></p>
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color:#1F497D">Options seem to fall into two camps - local, individual make-up air at the outer wall from a trickle vent or spot ERV, or else a central system ducted from
the corridor. <o:p></o:p></span></p>
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color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D">For local make-up air, one might ask if the trickle vent raises questions of thermal comfort and/ or additional heat load from unconditioned outside air,
and if the Spot ERV is thus a good alternative to help condition that make-up air. Other options might be based around centrally supplied make-up air, so to inform the cost-benefit comparisons it's great to hear input like yours. <o:p></o:p></span></p>
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color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D">David<o:p></o:p></span></p>
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color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> Tedd Weyman [mailto:weyman_tedd@yahoo.com]
<br>
<b>Sent:</b> Tuesday, February 22, 2011 7:10 AM<br>
<b>To:</b> David Posada<br>
<b>Cc:</b> greenbuilding@lists.bioenergylists.org<br>
<b>Subject:</b> ERV's<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Arial","sans-serif";color:black">I recently decided against using a spot ERV for a 5 room, 1200' sq cottage (radiant heat) because the local wind pressures and stack effects make the pressure drives on the exterior
just too overwhelming for a light weight, low-CFM, ERV. If your heat recovery and air exchange are not from a central system (i.e. powerful enough to take over the buildings climate, including ducting to all rooms), its unlikely a small ERV will be able to
overcome the external environmental forces on the building your describing (i.e small apartments or condos).<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Arial","sans-serif";color:black"> <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Arial","sans-serif";color:black">A normal kitchen exhaust (if its externally vented and not just an internal filter - has 400 to 1000 CFM) and your bathroom exhaust (120+ CFM) are more (locally) powerful than a
full sized, let alone a spot ERV and probably perfectly adequate to meet all the air exchange needs in small and medium sized living units. Timer controlled fresh air supply might be needed to complement/supplement the exhaust of a timed bathroom exhaust and during
the cooking cycles of the kitchen exhaust. Your under-door fresh air supply (allegedly fresh air) will defeat the spot HRV's performance (its not just a question of volume of air per minute, its the flow rate and pressures).<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Arial","sans-serif";color:black"> <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Arial","sans-serif";color:black">If you live in a apt/condo, under-the-door positive pressure from the hallway brings is ugly. Give me independent air such as the trickle-vent or a coordinated (with exhaust) timed
fresh air supply any day over the stale smells and particulates of fried fish, cigarettes, cat hair and marijuana smoke from the neighbours.
<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Arial","sans-serif";color:black"> <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Arial","sans-serif";color:black">I bet there are half a dozen other things you can do per unit for the same price (investment) as the spot ERV that will more constructively affect living climate, improve the air
quality, and conserve/recycle/reduce energy waste. <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Arial","sans-serif";color:black"> <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Arial","sans-serif";color:black">TW<o:p></o:p></span></p>
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