Thermaflex 54710000002 Flex-vent 10 in X 25 Ft R-4.2 Flex Duct

Product Description

The THERMAFLEX 54710000002 is a 10-inch diameter, 25-foot insulated flexible air duct rated at R-4.2, engineered for low- to medium-pressure HVAC air distribution systems. The inner core is a polyester film laminated over a heavy-gauge corrosion-resistant steel wire helix, providing structural support and shape retention. A thick fiberglass insulation blanket over a fiberglass scrim delivers the R-4.2 thermal performance, and a durable black polyethylene outer jacket serves as the vapor barrier. This duct is installed by HVAC technicians in residential and light commercial forced-air systems where flexible duct runs are required between plenums, branch takeoffs, and diffusers.

The 54710000002 is suited for residential air distribution and venting applications in low- to medium-pressure systems. Its oversized core allows proper fit over standard fittings and can be shaped to fit oval inlets without excessive effort. The duct handles operating temperatures from -20 degrees F to 250 degrees F and air velocities up to 5000 FPM, making it appropriate for typical residential supply and return branch runs. UL 181 listing and compliance with NFPA 90A and 90B, along with most state and federal code requirements, make it a straightforward specification for permitted work.

Key Features

• R-4.2 fiberglass insulation blanket over fiberglass scrim for thermal efficiency
• Corrosion-resistant steel wire helix inner core with polyester film laminate for durability and shape retention
• Black polyethylene outer jacket functions as integrated vapor barrier
• Oversized cores for proper fit on standard fittings; easily shaped to fit oval inlets
• Rated for velocities up to 5000 FPM and temperatures from -20 degrees F to 250 degrees F
• UL 181 listed; complies with NFPA 90A and 90B standards
• 5-year manufacturer warranty

Compatibility

Designed for use in residential forced-air HVAC systems as a flexible branch duct for supply air distribution and venting applications in low- to medium-pressure duct systems.

Installation Notes

Flexible duct installation is typically performed by licensed HVAC technicians in accordance with ACCA Manual D and local mechanical codes. Shut down and lock out the air handling unit before connecting or repositioning flex duct runs. Secure both ends with listed clamps or ties and mastic or listed tape per UL 181B-FX requirements — do not use standard cloth duct tape. Avoid sharp bends and excessive compression of the duct, as these reduce airflow and effective R-value.