Quietflex 7KM Flex Duct 7 Inches R-4.2 Foil Jacket 25 Foot

Product Description

The QUIETFLEX 7KM is a 7-inch diameter flexible duct designed for air distribution in residential and light commercial HVAC systems. It ships in a 25-foot length and carries an R-4.2 insulation value, helping maintain consistent supply and return air temperatures while limiting heat gain and loss through the duct wall. The outer jacket is a durable foil laminate that resists tearing and moisture intrusion. The flexible inner core supports smooth, low-turbulence airflow and allows the installer to route the duct around framing, joists, and equipment without rigid fittings at every turn.

This flex duct is suited for both supply and return air applications in residential forced-air systems and light commercial HVAC installations. It connects to standard round collars, takeoffs, and plenums sized for 7-inch ductwork. Typical install locations include attics, crawlspaces, and unconditioned chases where flexibility and insulation performance are both required. Licensed HVAC technicians and sheet metal contractors are the primary installers in new construction and retrofit work.

Key Features

• 7-inch inside diameter fits standard 7-inch round collars and takeoffs
• R-4.2 insulation value reduces heat transfer through the duct wall
• 25-foot length per section minimizes the number of connections in a run
• Foil outer jacket resists tearing, moisture, and common attic and crawlspace conditions
• Flexible inner core allows routing around obstructions without additional fittings
• Suitable for both supply and return air applications

Compatibility

Designed as an OEM-style replacement and new-construction option for residential and light commercial forced-air HVAC systems requiring 7-inch round flexible duct connections.

Installation Notes

Installation should be performed by a licensed HVAC technician or qualified sheet metal contractor in accordance with SMACNA flexible duct installation standards and local mechanical codes. Always power down the air handling unit and close the system before making duct connections. Secure both ends of the flex duct with approved clamps or draw bands and seal joints with UL 181B-listed mastic or tape to prevent air leakage. Avoid sharp bends, excess compression of the inner liner, or unsupported sags that can restrict airflow and reduce system efficiency.

Technical Specifications

• Inside Diameter: 7 inches
• Length: 25 feet
• Insulation R-Value: R-4.2
• Jacket Type: Foil laminate outer jacket
• Application: Supply and return air, residential and light commercial HVAC

Standard Information

• Brand: QUIETFLEX
• Manufacturer Part Number: 7KM