Knauf Fiber Glass: duct liner
Duct Liner E • M has been redesigned to provide improved thermal performance and now has an R-value of 4.2 and a K factor of .24. This meets the thermal performance requirements of many of the most stringent local and state energy codes, including Title 24, the California Building Standards Code, according to the manufacturer. Features of the new liner include an encapsulant edge coating that covers fibers and prevents flaring of the insulation at the edges, and mat facing that is treated with an EPA-registered anti-microbial agent to aid in the prevention of fungal and bacterial growth.
—Knauf Fiber Glass