Thermaflex 53808000001 Flex Duct 8in X 25ft R-6 Km

Product Description

The THERMAFLEX 53808000001 is an 8-inch diameter, 25-foot length of KM Flex-Vent insulated flexible air duct rated R-6. The inner core is a smooth, airtight polyester film laminated over a heavy-gauge, corrosion-resistant steel wire helix. This construction maintains airflow integrity under low-to-medium pressure conditions and supports velocities up to 5000 FPM. Surrounding the inner core is a thick blanket of fiberglass insulation. The outer jacket is a bi-directional, reinforced metallized vapor barrier that resists unraveling. Licensed HVAC technicians install this duct during system commissioning or retrofit work in residential and light commercial applications.

This flexible air duct is suited for low-to-medium static pressure supply and return duct runs in forced-air HVAC systems. It performs across a temperature range of -20 degrees F to 250 degrees F, making it appropriate for both heating and cooling distribution. The R-6 insulation value meets or exceeds energy code requirements in many jurisdictions for unconditioned space installations such as attics, crawlspaces, and plenums. It is a practical choice where rigid ductwork is impractical or where transitions and offsets require flexible routing.

Key Features

• 8-inch inner diameter x 25-foot length for standard residential and light commercial trunk-to-register runs
• R-6 fiberglass insulation blanket reduces heat gain and loss in unconditioned spaces
• Smooth polyester inner core promotes laminar airflow and low friction loss
• Corrosion-resistant steel wire helix innercore maintains shape under positive pressure up to 10 inches WG (for 4-inch through 16-inch ID sizes)
• Bi-directional reinforced metallized outer vapor barrier resists moisture infiltration and unraveling
• Rated for air velocities up to 5000 FPM and temperatures from -20 degrees F to 250 degrees F

Compatibility

Designed as an OEM-style flexible duct replacement or new-installation component for residential and light commercial forced-air HVAC systems requiring an 8-inch diameter insulated flex duct with R-6 thermal performance.

Installation Notes

Installation should be performed by a licensed HVAC technician in accordance with SMACNA guidelines and applicable local mechanical codes. Shut down and de-energize the air handling unit before connecting or disconnecting duct sections. Secure each end with an approved draw band or clamp and mechanically fasten to the collar before applying mastic or foil tape — do not rely on tape alone as the primary mechanical connection. Avoid sharp bends or excessive compression of the duct, as either condition reduces effective R-value and increases static pressure drop.