Flexduct 865C Flex Air Duct R-8 8 in 25 Ft Fiberglass Black

Product Description

The FLEXDUCT 865C is a UV-inhibited fiberglass flexible air duct rated at R-8 insulation value, designed for residential and light commercial HVAC distribution systems. Measuring 8 inches in diameter and sold in a 25-foot length, this flex duct provides thermal performance required in modern forced-air systems where energy codes demand higher insulation values. The black outer jacket resists UV degradation, making it suitable for installations in attics and crawlspaces with incidental light exposure. Licensed HVAC technicians install this duct as part of supply or return air distribution runs connecting air handling equipment to diffusers and grilles.

This flex duct is suited for residential split systems, heat pumps, gas furnace applications, and packaged units requiring insulated flexible distribution runs. The 8-inch diameter accommodates mid-range airflow branches off main trunks. The 25-foot bag length covers standard residential runs without splicing in many installations. It is commonly installed in attic spaces, conditioned crawlspaces, and framed ceiling cavities where rigid duct transitions to flexible branch runs.

Key Features

• R-8 insulation value meets current energy code requirements in most jurisdictions
• UV-inhibited outer jacket extends service life in attic and crawlspace environments
• Fiberglass construction provides lightweight handling and good thermal performance
• 8-inch diameter suits mid-capacity branch duct runs in residential systems
• 25-foot length reduces the number of connections needed on longer runs
• Black outer jacket finish for attic and low-light installation environments

Compatibility

Designed as an OEM-style replacement and new-installation flex duct for residential and light commercial forced-air HVAC systems requiring R-8 insulated flexible ductwork in 8-inch diameter configurations.

Installation Notes

Installation should be performed by a qualified HVAC technician in accordance with SMACNA guidelines and local mechanical codes. Power down the air handling unit before connecting or modifying duct runs. Avoid sharp bends that restrict airflow or compress the insulation, which reduces effective R-value. Secure all connections with approved clamps and mastic or UL-listed duct tape rated for flex duct applications.

Technical Specifications

• Insulation Rating: R-8
• Diameter: 8 inches
• Length: 25 feet
• Material: Fiberglass
• Color: Black
• UV Resistance: UV-Inhibited Outer Jacket
• Category: Flex Duct

Standard Information

• Brand: FLEXDUCT
• Manufacturer Part Number: 865C