Compare flex vs metal duct

Answer 1

Flex -VS- Ridged ductingThere is not a better or worse as far as flex vs. ridged. There is however a better or worse application of each.

Flex duct was designed to be used as a �Last 6 Feet� connector for drop ceiling applications. For this purpose there is nothing better. It also works great for multi radius connections over a short length (6 ft or less).

Ridged pipe is much better suited for longer, straighter runs. The pipe is much less restrictive and has a lower friction loss due to its smooth interior.

The ASHRE Design manual has great information on use of ducting materials.

Flex has become the materials of choice for ducting runs, only because the installers have become lazy and the company owners have become greedy. The installation cost is reduced because there is little or no time spent measuring and cutting duct to fit the application. Flex can be strung through rafters, over and around perlins, and comes in 25 ft lengths (shorter than most runs) reducing cuts and splices. It can also be strung too tight, smashed and bent to unreasonable restrictions and seldom if ever properly supported.

If used properly, flex is better than hot buttered toast. Done wrong, and reduced airflows, extreme temperature differentials and overall poor efficiency is the only possible outcome.

Answer 2

Flex duct is a flexible, insulated tube made of wire coil covered with plastic or foil. It is easier to install, but can be more prone to damage and restrictions in airflow. Metal duct is a rigid, usually galvanized steel, tube that provides better airflow and durability, but can be more challenging to install due to its rigid nature. The choice between flex and metal duct depends on factors such as installation space, budget, and desired airflow performance.