"Lee" wrote in message
.. .
I'm installing a bathroom exhaust fan, and I want to insulate the exhaust
duct. I'm planning to use 4" solid exhaust duct. Where can I find
insulation for this 4" round duct?.


Why not use the pre-insulated flexible duct? The big box stores around
here all carry it. Unless your run is really long, the extra losses
won't be an issue on the push side of the fan, and it will be quieter.

HTH,

Paul