A family member is having the duct work replaced in her house.

One company wants to use flexible insulated ducts which is much cheaper.

Another company wants to install insulated metal ducts saying the flexible ducts are hard to clean and blow fiberglass into the house.

I don't have experience with flexible ducts. Is one better than the other? Is regular insulated metal ducts worth twice as much to install?

Thanks

First off the flex duct is not likely to put any fibre glass into the air because the inner liner has a plastic inner wall separating the air flow from the fibre glass, where as the sheet metal duct may have insulation on the inside or be wrapped on the out side. The difference between them is the flex duct has more resistance to air flow because of the corrugated inner support, the installation of the flex duct should be done with the least amount of dips or sways in the duct , Good luck ,Mike

Yes your better off paying double to have it hard piped then with the flex. You don't need insulation if it's just warm air. You'll need to insulate the lines if you have A/C. Allways go with the metal, flex lines shouldn't be used.