Johns Manville Unfaced insulation is a lightweight thermal and acoustical fiber glass insulation made of long, resilient glass fibers bonded with an acrylic thermosetting resin. Unfaced batts are effective when controlling heat flow to the exterior, unwanted noise in internal walls, and to assist with moisture control, a separate vapor retarder can be applied. All Johns Manville Unfaced insulation products are made of naturally white, Formaldehyde-free fiber glass, lowering environmental concerns, including the risks of poor indoor air quality and the effects of manufacturing on the environment