The Residential Building Code calls for R-8 insulation for these ducts, but check with your building ... That didn't meet our ...

If your air duct system was installed before the 1970s, the HVAC insulation and adhesives used to wrap the air ducts might be asbestos-based and need to be removed by an asbestos professional.

Insulation surrounding ductwork that's wet will require replacement. Other surfaces within the HVAC system may be cleaned with a detergent solution and dried immediately afterward. Places that can be ...

If you're unsure (or if your situation is unsalvageable, with wet or moldy insulation ... "[Since] HVAC systems push air through the air ducts that run throughout the home in walls, ceilings ...