JM ComfortTherm poly-encapsulated thermal and acoustical fiber glass insulation is lightweight and made of resilient, long glass fibers bonded with our bio-based binder. ComfortTherm is wrapped in plastic for more comfortable installation with less itch and dust. The product is available with a vapor-retarder plastic facing, and also with a plastic facing that does not act as a vapor retarder for use in hot, humid climates.