Winterizing Your Home
Q: I´m trying to winterize my house. Which is better for insulating attics - fiberglass or cellulose?
A: Both are excellent materials for insulating an attic.
But the cellulose is generally easier to install and less expensive. Cellulose has a slightly higher R-value per inch of thickness, and it´s more effective at reducing air leakage. Studies have shown that, compared to fiberglass, cellulose also retains its insulating value at lower temperatures. Based on these points, cellulose is the preferred insulation for most attic arrangements.
Regardless of which material you use, be sure to seal all holes in the attic floor before beginning to insulate.
More information about saving energy is available at Kansas State University´s Energy Extension Service.
Source: Bruce Snead, Kansas State University Energy Extension Service