Fiberglass insulation comes in R-values ranging from R-11 to R-38 in rolls and batts, or can be blown into an attic to almost any R-value desired.
Fiberglass retains its shape and does not settle, sag or lose its R-value over time. The R-value of fiberglass is based on its full thickness and is diminished if it is compressed or forced into cavities. Fiberglass is a lightweight, naturally non-combustible material made from sand and recycled glass. Fiberglass insulation is non-absorbent and will not retain moisture. The open fiber construction provides acoustical benefits, but compromises the R-factor in extreme sub-zero temperatures.
Large Amounts of Energy Required for Production
Fiberglass does not qualify for a eco-friendly Green rating because it utilizes only 0% to 30% of recycled content and is manufactured in facilities that engage high temperature furnaces that burn natural gas and release CO2 resulting in an embodied energy of up to 12,000 BTU per pound of product.