On Wed, 24 Apr 2013 12:36:14 -0400, Jim Elbrecht
wrote:

On Wed, 24 Apr 2013 05:25:33 -0700 (PDT), wrote:

Can I use fiberglass bat to insulate the main and branch ductwork in my crawlspace?

How long has the duct been there? Might be a better plan to just
replace it with insulated duct.

I used the flexible round duct. It was dirt cheap- and *way* easier
than cleaning the old ductwork, then figuring out how to wrap it in
insulation.

The down side is that in the 10 yrs since I installed it, I've had one
duct that a mouse decided to chew through and nest in. Now *that*
made a disgusting mess when the heat came on that fall.

Jim
You won't catch me EVER using flex duct. Anywhere. For ANY reason.