Flexible ducts are a great option for many residential applications due to their cost-effectiveness, simple installation process, and durability. They are made of materials such as fiberglass, vinyl, or reinforced fabric, making them lightweight and easy to fit in tight spaces or in the corners of homes with non-traditional designs. When considering material, installation, and labor costs, flexible ducts are more economical than metal ducts. Installing them requires less skill and effort than metal ducts, which are almost twice as expensive and require considerable effort to seal joints, seams, and elbows.
However, there is no need to replace existing ducting with flexible insulated ducting unless the existing ducting has rusted. Flexible ducts not only resist airflow but are also more susceptible to poor installation. Many factors can fail such as a poorly sealed joint, excessive unsupported length, and wrinkled sections. In addition, the material itself is less durable than sheet metal.
Systems with flexible ducts require more frequent maintenance by an HVAC expert.This is because flexible ducts often wrinkle in ways that make it difficult for air supply to reach the designated roof vent.
Regardless of the type of ducts in your building, the air conditioning system needs regular maintenance to perform at its best. For more information on how to choose ducts for a healthy home, read Daniel Glickman's Q&A section: Should we replace our flexible PVC-coated heating ducts with other types of ducts?.