Figure 2.2 — At very cold temperatures, when the temperature difference across the attic insulation reaches a certain critical point, convection within the insulation can reduce r-value (J.D. Ned Nisson, “Attic Insulation Problems in Cold Climates,” Energy Design Update, March 1992, 420-43)

Figure 2.2 — At very cold temperatures, when the temperature difference across the attic insulation reaches a certain critical point, convection within the insulation can reduce r-value (J.D. Ned Nisson, “Attic Insulation Problems in Cold Climates,” Energy Design Update, March 1992, 420-43)