Are flexible heating ducts allowed in attic? House has attic furnace.

Answer 1

Hi Scott,

As far as I know there's no restrictions to use flexible heating ducts in a house attic for as long as they are listed for that purpose and installed accordingly to their manufacturer's specifications (straps, tape, support, etc.).

There is always a possiblity that some local laws will limit their usage but I'm not aware of any. You may want to call your local building department to verify that.