I am building a home for my wife and I in the mountains of NC. I am trying to size a fan for an exhaust only ventilation system. I am thinking of using a fan designed for radon mitigation. I think I want about 80-100 cfm. Thought?
GibBarrus
| Posted in General Questions on
The house volume is about 32000ft^3, including a full basement. The roof deck will be insulated with spray foam. I am planning to position the exhaust inlet near the peak of the roof, in a small attic above the bathroom. The attic space is inside the conditioned envelop.
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Replies
In a tight house where will the supply air come from? What about filtering the supply air? Those white pines in WNC are going to start throwing off a ton of pollen after all.
https://buildingscience.com/documents/insights/bsi069-unintended-consequences-suck
IMO I would use a supply-only approach before entertaining exhaust only because the air would be filtered and I you needed you could put bath fans on a timer.
Gib,
If you haven't already, be sure to read these two articles. If you are building a pretty good house (one with above code levels of air sealing and insulation), you don't want any missteps with your ventilation strategy. (Also check out the sidebar links.)
https://www.greenbuildingadvisor.com/blogs/dept/musings/designing-good-ventilation-system
https://www.greenbuildingadvisor.com/blogs/dept/musings/how-much-fresh-air-does-your-home-need