Thermaflex 54208000001 Flex Duct 8 Inch X 25 Ft R-6

Product Description

The THERMAFLEX 54208000001 is an 8-inch diameter, 25-foot length insulated flexible air duct rated R-6, designed for low to medium pressure HVAC distribution systems. The inner core is a polyester film laminated over a heavy, corrosion-resistant steel wire helix, providing structural support and airflow integrity under pressure. A thick blanket of fiberglass insulation wraps the core over a fiberglass scrim, and the outer jacket is a durable black polyethylene vapor barrier. This duct is installed by licensed HVAC technicians in residential and light commercial air distribution applications where flexibility, insulation performance, and pressure resistance are required.

This flexible duct is suited for supply and return air branch runs in low to medium pressure forced-air systems. The R-6 insulation value makes it appropriate for unconditioned spaces such as attics and crawlspaces where thermal and condensation control are critical. The 8-inch inner diameter accommodates standard trunk-to-branch transitions in residential and light commercial ductwork layouts. It is available across a diameter range of 4 to 20 inches for system-wide flexibility.

Key Features

• R-6 insulation value for thermal performance in unconditioned spaces
• Steel wire helix inner core provides corrosion resistance and structural support
• Polyester film inner liner laminated and encapsulated over the wire helix
• Fiberglass insulation blanket over fiberglass scrim for consistent thermal coverage
• Durable black polyethylene outer vapor barrier jacket
• Rated for maximum air velocity of 5,000 FPM
• Temperature range from -20 degrees F to 250 degrees F

Compatibility

Designed for use in low to medium pressure forced-air HVAC distribution systems. Available in inner diameters from 4 to 20 inches, making it compatible with standard residential and light commercial duct fittings and collars within that size range.

Installation Notes

Installation should be performed by a licensed HVAC technician in accordance with SMACNA flexible duct installation standards and local mechanical codes. Disconnect and lock out the air handler or furnace before connecting or repositioning duct sections. Avoid sharp bends, compression, or kinking of the flexible duct, as these conditions reduce airflow and degrade insulation performance. Secure connections at both ends with approved clamps and mastic or UL 181B-listed tape.