Dr. Allison A. Bailes III writes that flex duct is the “bane of home performance contractors and green builders everywhere.” It isn’t that he thinks good flex duct installation is impossible, just very rare. Because of the many abuses and problems present with flex duct, including kinks and sharp turns, long and poorly supported ducts, overcrowded radial systems, extra duct length not removed, poorly fastened and sealed connections, and joints that are sometime simply taped together, Bailes wonders if flex duct ought not to be banned from green building projects completely. A better alternative he presents is rigid sheet metal, or hard pipe. One benefit to hard pipe is that it must be specifically designed.
Read the full article here: Should Flex Duct be Banned?