When you talk about a house breathing, think about an airplane flying.
The airplane flys differently than a bird, but both accomplish the same
thing. I think a house can PERSPIRE naturally (i.e. build a house
without a diffusion retarder) as long materials are selected carefully,
but then, natural perspiration probably isn't going to handle the amount
of moisture generated inside most houses. For the benefit of people, you
must provide an air exchange, so you need an air-pressure difference to
push air through holes (either random holes or deliberate holes). I just
think a fan does a better and more reliable job than Mother Nature.
-- John Bower, The Healthy House Institute http://www.hhinst.com/ email: healthy@bloomington.in.us 430 N. Sewell Road, Bloomington, IN 47408 Phone/fax 812-332-5073 __________________________________________________________________ This greenbuilding dialogue is sponsored by Oikos (www.oikos.com) and Environmental Building News (www.ebuild.com). For instructions send e-mail to greenbuilding-request@crest.org. __________________________________________________________________