Published R-value for climate-zone packages
Pink fiberglass batts and loosefill systems ship with thickness charts that energy modelers cite when IECC climate zones demand R-38 attics or R-20 walls. Specifiers avoid speculative derates by matching facing type, compression limits, and vapor retarder orientation to the wall drying strategy—not a single national default. Limit to note: published cavity R-value assumes full thickness; compressed batts at wiring or overdriven staples erase that number in the field.