A while back I read an article that was talking about how batt insulation is not an air barrier. Air can just flow right through it lowering the R-vaule to almost nothing. A fact that I was already aware of. I got to thinking about underneath my own house, a vented crawlspace, I have insulation in between my joists that is exposed to air, without an air barrier on the underside of it. Is the R-19 batt insulation I have under my house preforming at a much lower value because the air can get through it? Please forgive my ignorance. This is so common Im sure there is a reasonable explanation but it got me thinking. Thanks in advance!
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