One important alternative to fiberglass (link) insulation is cellulose. Cellulose is installed with machines that blow it into attics or spray it into wall cavities. Cellulose is made from shredded newspaper and is a good insulator because wood, from which the paper is derived, has a heat-resistant cellular structure. Typical R-values range from 3.5 to 3.7.Cellulose loose-fill offers the same benefits over fiberglass blankets as fiberglass loose-fill does: it is more effective at insulating an entire space because it can fill oddly shaped spaces and let less air through. In spaces like attics where the insulation rests on the floor, dry cellulose can be blown in, while in vertical spaces like wall cavities the shredded newspaper can be purchased that is dampened and sprayed into place to ensure even, effective application. This technique is used more often in new constructions.

For more information on cellulose loose-fill, please visit:

U-Mass Dept. of Natural Resources Conservation: A guide to cellulose with useful tips on installation

DIY Network: A brief guide to cellulose installation

Link to: Cellulose v. Fiberglass

Link to: Fiberglass

Link to: Insulation