Quietflex 12KM Flex Duct 12 Inch R-4.2 25 Foot Foil Jacket

Product Description

The QUIETFLEX 12KM is a 12-inch diameter, foil-jacketed flexible insulated duct designed for air distribution in residential and light commercial HVAC systems. Each section is 25 feet long and carries an R-4.2 insulation value, reducing heat loss and helping maintain consistent supply and return airflow. The outer jacket is constructed of durable foil material that resists tearing and moisture infiltration. The flexible inner core promotes smooth, low-turbulence airflow and contributes to quiet system operation. This duct is suited for both supply and return air runs where thermal efficiency and installation flexibility are required.

The QUIETFLEX 12KM is appropriate for residential new construction, retrofit projects, and light commercial HVAC installations. It works in both supply and return air applications and is commonly routed through attics, crawlspaces, and framed cavities where rigid ductwork is impractical. The 25-foot length reduces the number of joints needed on longer runs, which lowers potential leakage points and simplifies layout in tight spaces.

Key Features

• 12-inch inner diameter supports high-volume airflow on main supply and return branches
• R-4.2 insulation value limits heat transfer in unconditioned spaces such as attics and crawlspaces
• Foil outer jacket resists tearing, puncture, and moisture during and after installation
• 25-foot section length reduces joint count on longer duct runs
• Flexible core allows routing around obstructions without rigid fittings
• Suitable for both supply and return air applications

Compatibility

Designed as an OEM-style replacement and new-installation flexible duct for residential and light commercial HVAC air distribution systems requiring a 12-inch diameter insulated duct with foil jacket construction.

Installation Notes

Flexible duct of this diameter is typically installed by licensed HVAC technicians in accordance with local mechanical codes and SMACNA duct installation standards. Power down the air handling unit and close the system before making duct connections. Secure each end with approved metal draw bands and seal connections with UL 181-rated mastic or foil tape to minimize air leakage. Avoid sharp bends or compressed sections, as these restrict airflow and reduce system efficiency.

Technical Specifications

• Inner Diameter: 12 inches
• Length: 25 feet
• Insulation R-Value: R-4.2
• Jacket Material: Foil
• Application: Supply and Return Air

Standard Information

• Brand: QUIETFLEX
• Manufacturer Part Number: 12KM