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.
Below Deck Spray Foam Insulation for Existing Roofs Description Guide describing how to add spray foam insulation to the underside of the existing roof deck as part of the conversion of a vented attic to an unvented, insulated attic.
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.
Ducts Buried in Attic Insulation and Encapsulated Description Guide describing approaches to burying and encapsulating ducts in unconditioned attics to increase the overall R-value of duct insulation.