Thermaflex 56305000002 Flex-vent R-8 Insulated Flex Duct 5 in X 25 Ft

Product Description

The THERMAFLEX 56305000002 is an R-8 insulated flexible air duct in the KM Flex-Vent series, designed for low- to medium-pressure HVAC air distribution systems. The inner core is a smooth, airtight polyester film that minimizes airflow resistance and supports clean, efficient distribution. Encapsulating the inner core is a heavy-gauge, corrosion-resistant steel wire helix that maintains round cross-section under compression and bending. A thick fiberglass insulation blanket surrounds the core, delivering an R-8 thermal value. The outer jacket is a bi-directional reinforced metallized vapor barrier that resists unraveling and protects insulation integrity. Licensed HVAC technicians and sheet metal installers use this duct in residential and light commercial supply-air applications.

This flexible duct is suited for supply-air branch runs in residential forced-air systems and light commercial HVAC installations. Its 5-inch inside diameter fits standard branch takeoffs and boot fittings common in residential trunk-and-branch and radial plenum layouts. The R-8 insulation value meets or exceeds energy code requirements in many climate zones, making it appropriate for attic, crawlspace, and unconditioned-space installations where thermal loss is a primary concern. The 25-foot length accommodates most single-branch runs without a splice.

Key Features

• R-8 fiberglass insulation blanket for high thermal efficiency in unconditioned spaces
• Smooth polyester inner core engineered for low- to medium-pressure airflow systems
• Corrosion-resistant steel wire helix maintains duct shape and prevents collapse
• Bi-directional reinforced metallized outer vapor barrier resists unraveling and moisture infiltration
• Rated for velocities up to 5000 feet per minute
• Operating temperature range of -20 degrees F to 250 degrees F
• 5-year manufacturer warranty

Compatibility

Designed as an OEM-style replacement and new-installation flexible duct for residential and light commercial forced-air HVAC supply systems with 5-inch branch connections. Positive pressure rating is 10 inches water gauge for 4-inch through 16-inch inside diameter sizes; negative pressure rating is 1/2 inch water gauge across the full 4-inch to 20-inch inside diameter range.

Installation Notes

Installation should be performed by a licensed HVAC technician or qualified sheet metal installer in accordance with SMACNA flexible duct installation standards and applicable local mechanical codes. Power down and lock out the air handler or furnace before connecting or replacing duct sections. Avoid sharp bends and compression that reduce the duct's effective cross-sectional area and increase static pressure drop. Secure both ends with approved duct clamps or ties and seal with UL 181B-listed mastic or tape before covering with insulation jackets at connections.