Building Cavities Not Used as Supply or Return Ducts Description Guide describing the use of building cavities as supply or return ducts.
Ducts Buried in Attic Insulation and Encapsulated Description This guide describes approaches to buryng and encapsulating ducts in unconditioned attics to increase the overall R-value of duct insulation.
Unvented Conditioned Attic with Spray Foam Insulation Below Roof Deck Description Guide describing a method for insulating an unvented attic by spraying foam insulation along the underside of the roof deck.