attic: cellulose or fiberglass in cold climates
In case you all haven't seen this, it applies to anyone's decision whether to blow in cellulose or fiberglass in cold climates:
"There is a problem with loose-fill fiberglass attic insulation is cold climates. It appears that, as attic temperature
drops below a certain point, air begins to circulate into and within the insulation, forming "convective loops" that
increase heat loss and decrease the effective R-value. At very cold temperatures (-20F), the R-value may
decrease by up to 50%."
In full-scale attic tests at Oak Ridge national Laboratory, the R-value of 6 inches of cubed loose-fill attic insulation
progressively fell as the attic air temperature dropped. At -18 F, the R-value measured only R-9. The problem
seems to occur with any low-density, loose-fill fibrous insulation.
Nisson, J.D. Ned, JLC, "Attic Insulation Problems In Cold Climates" March 1992, pp 42-43
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