Core TradesQuestion 117 of 700
Fiberglass batt insulation is compressed and stuffed tightly around wiring and into a cavity that is too shallow. The effect on thermal performance is:
a.No change; compression does not matter
b.Reduced R-value because compressed batts lose loft and trapped air space
c.Increased R-value because it is denser
d.It becomes a vapor barrier
Explanation
Batt insulation relies on trapped air in its loft; compressing it reduces thickness and trapped air, lowering the effective R-value. Density does not raise R-value in this case, compression does matter, and it does not turn into a vapor barrier.
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