On Tue, 18 Jan 2011 18:26:29 -0800 (PST), "hr(bob) "
wrote:


The label on it said * flex duct * *but when I looked that up on the
web all I found were long truly flexible ducts with built-in
insulation that contractors now use sometimes to go from the main duct
to individual rooms. *

Thanks.

It is used to isolate noise from one part of the system into another
part of the system. It is frequently found on the input and output
sides of the main duct fairly close to the furnace/air conditioning
unit to isolate motor/fan noise.

Yeah, thanks. Mine don't have holes yet, but I think that will be
soon.