Convective loop in Fiberglass Insulation
fingersandtoes
| Posted in Energy, Heating & Insulation on
I remember a thread in which Dovetail and BillHartmann linked to studies that showed there was no significant convective loop in fiberglass insulated stud bays, and yet in this months FHB there is a diagram showing just that. Has there been new evidence, or is this just an erroneous “fact” that keeps being perpetuated?
Replies
Unless the article has linked source that is new then I would say
the latter as near as I can tell.
There is a distinct possibility of a convective loop occurring with really haphazardly installed batts however. Would have to be a really bad job though IMO.
It does mention the loop occurs "around poorly installed batts" but that doesn't seem fair when the walls filled with cellulose and foam make no reference to what would occur in the case of poor installation.
Well my research of the claims that wall cavity batts had convection loop all got back to the competitors cherry picking partial facts from the tests that were run. Called marketing... I wouldn't expect them to point out there own materials have the same issues.
Life is Good
but even poorly installed Cell is still going to fill the bay front to back. The only voids would be at the top unless gravity fails us.
My house is 1.5 stories with knee walls in the upstairs. The builder installed bats in the 1st floor cieling joists to just beyond the upper knee walls.....except he didn't put any blocking in behind the bats. Air would enter at soffits on one side of the house travel over the top of the bats over my uninsulated floor/ceiling and exit the other soffit. I had to retro in a ton of cells to fill the joist bays to fix it. Anybody that opens the ceilings in my 1st floor is going to cuss me till the cows come home.
I think the key word is "significant". And what is "significant" (outside of statistics) is in the eye of the beholder.