Knauf EcoRoll R-13 Foil-Faced Insulation vs Johns Manville R-13 Kraft-Faced Insulation

Both are R-13, 3½-inch fiberglass rolls, 15 inches wide by 32 feet, covering 40 sq ft for 2x4 walls at 16-inch centers. The real split is the facing: Knauf's foil is a tighter vapor retarder at 0.05 perms, while Johns Manville's kraft facing is the more common choice for standard wood-frame walls and is formaldehyde-free with GREENGUARD Gold and SCS certification. Pick foil where moisture control matters most, such as humid rooms or colder climates; pick kraft for typical interior and exterior wood-stud jobs where you want a familiar, certified, low-odor product.

• Choose the Knauf EcoRoll if you want a foil vapor barrier with very low permeance for moisture-sensitive walls and a soft, low-dust roll that cuts cleanly.
• Choose the Johns Manville roll if you are insulating standard 2x4 wood-stud walls and want a formaldehyde-free, GREENGUARD Gold certified kraft-faced roll with staple flanges.