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<div>I don't know, John. Gerbils have been tested in way more than 100,000 homes, and I don't know of an electric fan that can reproduce itself. Gerbils routinely reproduce themselves inside a home's air ducts! On the other hand, gerbils also produce other
things, so maybe I would prefer to use electric fans after all. </div>
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<div>Derek</div>
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<div>On Mar 21, 2013, at 10:30 AM, John Straube wrote:</div>
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<div>Chris, I have been trying to figure out simple ventilation systems for decades.<br>
The challenge is not the path of air (hot air collectors, earth tubes, trombe walls) it is the driving force. Solar driven systems only work for sunny hours when sunny. Not having ventilation for 14 hours a day in winter does limit the quality of air you
can get. <br>
It is unclear to me why people who have fridges (hermetically sealed, high compression systems, with synthetic lubrication, man made gasses) and computers for email, are so dead set against one of the first and simplest uses of electricity.<br>
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My simple, easy system works if you have a ducted furnace or air con system. Single duct to the outside connected to return duct with a FanCycler control ensuring that regardless of the wether fresh air is filtered, delivered to each room and mixed within
the home. In the order of $300-400 in practise. Proven in 100,000+ homes, requires special care in really cold and really humid climates. Requires a bathroom fan and ideally a kitchen range hood.<br>
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Small simple house with radiant, baseboard, or wood heat in cold climates: a $150 in-line fan exhausting from a single point near kitchen/main living area, trickle vents in important rooms.<br>
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Pie in the sky: a stack effect, solar assisted, wind-assisted passive device to replace the fan. This is basically a chimney and would work only in cool or cold or neutral temperature weather. An aerodynamically balanced damper would control the exhaust air
flow rate to account for the wildly varying driving forces. This has not been invented yet, let alone tested and marketed.<br>
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John<br>
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On 2013-03-20, at 1:44 PM, Chris Magwood <<a href="mailto:chris@endeavourcentre.org">chris@endeavourcentre.org</a>> wrote:<br>
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<blockquote type="cite">For me, the question is not whether to build appropriately air-tight and well insulated buildings, or whether to ventilate them. The question is how much ventilation is required and can it be done in a more passive manner.<br>
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<blockquote type="cite">What seems to be needed is a look at how much ventilation is required. Right now, this particular home is designed to Ontario Building Code standards for "required" ventilation to each designated room in the house. These standards, I'm
assuming, were developed for homes that have little or no moisture storage capacity in the building materials and a certain amount of offgassing from materials in the home. I'm sure that our "vapour-open" home with the large storage capacity of timber subflooring,
clay plasters and wood ceilings in the bathrooms, and no impermeable paints even on the drywall sections, does not need the prescribed amount of ventilation to ensure that there is no moisture condensing on the walls or windows. And given that no material
in the home contains toxins (or at least identifiable toxins), we probably don't need code levels of ventilation to flush the poisons.<br>
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<blockquote type="cite">So the question I have is this: Can we figure out ways to passively (or with gentle mechanical persuasion) ventilate such a home adequately? Solar hot air collectors? Earth tube ventilation? Vent tubing in trombe walls? Solar exhaust
fans? Air intake through heated slabs? Gerbil propelled fans in each room?<br>
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John Straube<br>
<a href="http://www.JohnStraube.com">www.JohnStraube.com</a><br>
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<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; ">Derek
Roff<br>
<a href="mailto:derek@unm.edu">derek@unm.edu</a><br>
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