Batt Insulation for Existing Vented Attics Description Guide describing how to increase insulation in existing homes by installing batt insulation on the ceiling plane of a vented attic.
Blown Insulation for Existing Vented Attic Description Guide describing how to insulate a vented attic in an existing home using blown insulation added to the attic floor.
Ducts Buried in Attic Insulation Description Guide describing buried ducts in loose-fill attic insulation, a method that can only be used in dry climates.