Flexible Duct Damper

[DavidPJ]

We have a 2 year old home with insulated flexible ducts from the plenum to the registers. Is it possible to install manual dampers in these ducts? The number 6" is written on the outside of the duct insulation. I assume that's the size of the flexible duct.

Is the flexible duct cut, then a damper inserted and joined with the ends of the cut flexible duct?

I'm trying to better balance our system for winter usage.

Thanks.

[Gunslinger]

put the damper where the flex leaves the box. This will keep noise down. You can put the damper in the collar.

[DavidPJ]

Thanks gunslinger.

[REP]

Its hard to say much without seeing some pictures but if you are having problems with airflo I'm willing to bet that its the flex causing the problems.
Most people plan for about 100 cfm s coming to their registers.You would be lucky to get 75 cfms with 6" flex.Even if its installed right you would have to go up tp 7".
Flex should be as short as possible,stright as an arrow,hung properly,and bends should be sheet metal.
AS Gunslinger said,the take off s should be metal and a damper installed in that.
The best system would be all metal and insulated on the outside.
Your other problem is the return air.I can't see it but I'll bet its too small .Also a central return will not make remote room comfortable.