Certainteed 409688 Duct Liner 2 Inches

Product Description

The CERTAINTEED 409688 is a 2-inch duct liner designed for installation inside sheet metal ductwork in forced-air HVAC systems. Duct liner reduces heat transfer through duct walls and attenuates airborne sound generated by air movement and mechanical equipment. It is installed on the interior surfaces of rectangular or round ducts before assembly, making it a standard material in both new construction and duct renovation projects. HVAC technicians and sheet metal contractors select this product when system design calls for combined thermal and acoustic control within the air distribution system.

This duct liner is suited for use in residential and light commercial forced-air systems where duct runs pass through unconditioned spaces or where noise transmission is a concern. Typical applications include supply and return air duct interiors in rooftop unit installations, air handling unit plenums, and trunk line ducts. The 2-inch thickness provides a meaningful increase in thermal resistance and sound absorption compared to thinner liner options.

Key Features

• 2-inch thickness delivers enhanced thermal insulation and acoustic attenuation for interior duct applications
• Designed for installation on the interior surface of sheet metal ductwork prior to duct assembly
• Serves dual function as both a thermal barrier and a sound-absorbing liner within the air distribution system
• Appropriate for supply and return air duct systems in residential and light commercial HVAC installations

Compatibility

Designed as an OEM-style liner material for interior installation in rectangular and round sheet metal ductwork used in forced-air HVAC systems.

Installation Notes

Duct liner is typically installed by sheet metal contractors or licensed HVAC technicians in accordance with SMACNA duct construction standards and local mechanical codes. The air handling system should be fully de-energized before working inside any duct section. Liner must be secured using approved adhesive and mechanical fasteners to prevent delamination or air stream dislodgement during system operation. Always verify that the installed liner does not reduce the net free area of the duct below design specifications.

Technical Specifications

• Thickness: 2 inches

Standard Information

• Brand: CERTAINTEED
• Manufacturer Part Number: 409688