Blown-in cellulose insulation is a very cost effective upgrade to batted fiberglass insulation. Cellulose is more densely packed than batted fiberglass, so air movement through the insulation is greatly reduced. This means the air you pay to heat and condition is kept in the living space and not traveling into the attic. This will also reduce the chance of any air that leaks into the attic from outside pushing its way into the home. We used blown in insulation to insulate this Middletown, DE attic.