[TGTIW]

There seems to be a wealth of information and resources among the members here, so I'm hoping someone can give me some advice regarding the HVAC ducting I have in my crawlspace. The ducting is roughly 20 years old and rather worn, I'm getting a good amount of condensation forming on it. I realize this also indicated that my crawlspace retains a good amount of humidity, but one problem at a time. I got a rather outrageous quote to replace and reinsulate the ducting, and I'm considering just doing it myself. Off of the main supply line branches off a number of ducts running to the floor registers. Each branch has a rigid duct, with flexible duct connecting it to the register and supply line. Would there be and issue with just replacing the entire run with a flexible line? If it's properly supported and doesn't have any severe bends, would the airflow be restricted at all?