Thermaflex 52304000002 Flex-vent R-8 Insulated Flex Duct 4 in X 25 Ft

Product Description

The THERMAFLEX 52304000002 is an R-8 insulated flexible air duct designed for low to medium pressure HVAC distribution systems. The inner core is constructed from a polyester film laminated around a heavy-gauge, corrosion-resistant steel wire helix, providing structural integrity and collapse resistance. A thick fiberglass insulation blanket over a fiberglass scrim delivers the R-8 thermal performance. The outer vapor barrier is a durable black polyethylene jacket that protects against moisture infiltration. This duct is rated for airflow velocities up to 5000 FPM and handles temperatures from -20 degrees F to 250 degrees F. Licensed HVAC technicians install this product in residential and light commercial air distribution applications.

This flexible duct is suited for branch runs in forced-air systems where a semi-rigid or rigid duct transition is not practical. The 4-inch inside diameter and 25-foot length make it appropriate for individual supply runs connecting a main trunk or plenum to a diffuser or register boot. Its rated positive static pressure of 10 inches WG (for 4-inch through 16-inch ID sizes) and negative pressure rating of 0.5 inches WG support standard residential and light commercial air handler configurations. The R-8 insulation value meets or exceeds many local energy code requirements for attic and unconditioned-space duct installations.

Key Features

• R-8 fiberglass insulation blanket over fiberglass scrim for high thermal performance
• Corrosion-resistant steel wire helix inner core laminated with polyester film
• Durable black polyethylene outer vapor barrier jacket
• Rated for airflow velocity up to 5000 FPM
• Operating temperature range: -20 degrees F to 250 degrees F
• Positive pressure rating of 10 inches WG for 4-inch to 16-inch ID sizes
• 5-year manufacturer warranty

Compatibility

Designed for use in low to medium pressure forced-air HVAC systems. Suitable for residential and light commercial supply and return air branch duct runs where a 4-inch inside diameter flexible duct with R-8 insulation is specified.

Installation Notes

Installation should be performed by a licensed HVAC technician in accordance with applicable mechanical codes, including SMACNA flexible duct installation standards. Power down the air handling unit and confirm zero airflow before cutting or connecting duct sections. Avoid sharp bends, compression, or excessive sag that reduce effective airflow and thermal performance. Secure connections at both ends with approved clamps and mastic or UL 181B-rated tape before sealing the insulation jacket.