Thermaflex 55808000001 Insulated Flex Duct 8 in 25 Ft R6

Product Description

The THERMAFLEX 55808000001 is an insulated flexible duct rated at R6 insulation value with an 8-inch inside diameter and a 25-foot length. Constructed from fiberglass and chlorinated polyethylene, it handles a temperature range of -20 to 250 degrees F and carries a vapor transmission rating of 0.05 perms — keeping moisture intrusion low in conditioned air applications. The silver outer jacket is a standard indicator of a vapor-barrier-wrapped flex duct. This product is installed by licensed HVAC technicians as a distribution component connecting supply plenums or branch takeoffs to diffusers and registers in residential and light commercial forced-air systems.

This insulated flexible duct is suited for pressure heating and cooling systems where both positive and negative static pressures are present. The 8-inch diameter is commonly used on trunk-to-register branch runs in mid-to-large residential systems or light commercial applications requiring higher airflow capacity. The 25-foot coil length provides enough material for a single long branch run or multiple shorter runs without splicing. The R6 insulation rating meets or exceeds common energy code minimums for duct insulation in unconditioned spaces such as attics and crawlspaces.

Key Features

• R6 insulation value meets energy code requirements for ducts in unconditioned spaces
• 8-inch inside diameter supports higher-volume branch runs in residential and light commercial systems
• 25-foot length reduces the need for field splicing on longer runs
• Rated from -20 to 250 degrees F for compatibility with both heating and cooling airstreams
• 0.05 perms vapor transmission rating limits moisture infiltration through the duct wall
• Positive 10 in-WG and negative 1 in-WG pressure ratings support standard forced-air system operating pressures

Compatibility

Designed for use with pressure heating and cooling systems. Suitable as an insulated branch duct in forced-air HVAC distribution systems where R6-rated flexible duct is specified.

Installation Notes

Installation is performed by licensed HVAC technicians. Power down the air handling unit and confirm the system is depressurized before cutting into existing ductwork. Secure both ends of the flex duct with approved sheet metal screws and listed duct tape or mastic sealant per the International Mechanical Code and applicable local codes — do not rely on friction fit alone. Avoid sharp bends and excessive compression of the duct body, as both conditions reduce effective airflow and can degrade insulation performance.

Technical Specifications

• Type: Insulated Flexible Duct
• Inside Diameter: 8 inches
• Length: 25 feet
• Insulation Value: R6
• Pressure Rating: Positive 10 in-WG / Negative 1 in-WG
• Temperature Rating: -20 to 250 degrees F
• Vapor Transmission: 0.05 Perms
• Material: Fiberglass / Chlorinated Polyethylene
• Finish: Silver

Standard Information

• Brand: THERMAFLEX
• Manufacturer Part Number: 55808000001