Which is better for an attic?

The Owens Corning roll. Its 23-inch width and 75 sq ft coverage cover attic joist bays faster, and the faced version adds a vapor retarder.

Which is better for interior walls?

The Knauf roll. It is unfaced, so it will not trap moisture inside interior wall cavities, and it is GREENGUARD Gold certified.

Is the Owens Corning roll worth the extra cost?

It is not extra: at $48.97 it is cheaper than the Knauf roll at $53.99 and covers about 26 more square feet per roll.

Which is better for sound control?

Both list acoustic insulation. The Knauf roll is marketed for sound control and is lighter, but the Owens Corning roll's greater width fills more of a stud bay per piece.

Do I need a vapor barrier with either?

Only the faced Owens Corning roll includes one. The Knauf roll is unfaced, so add a separate vapor retarder on exterior walls in cold climates.

Both are fiberglass and last the life of the building when kept dry. Neither product lists a service life, and moisture damage, not age, is what shortens either one.

Owens Corning R-19 Faced Fiberglass Insulation Roll 23 in. x 39.2 ft vs Knauf R-19 Unfaced Fiberglass Insulation Roll

Buy the Owens Corning roll for most wall and attic jobs: it is wider, faced, and cheaper at $48.97 at its lowest recent price versus $53.99 for the Knauf roll. Buy the Knauf roll if you need unfaced insulation for interior walls or between floors and want GREENGUARD Gold certification. The Owens Corning roll covers 75.07 sq ft; the Knauf covers 48.96 sq ft per pack, so Owens Corning costs less per square foot at these prices.

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