Mueller Streamline 7KMR8 Flex Duct 7 in R-8 Foil 25 Ft

Product Description

The MUELLER STREAMLINE 7KMR8 is a flexible HVAC duct designed for branch-run distribution in residential and light commercial air handling systems. It features R-8 insulation and a foil jacket that together reduce heat gain and heat loss in unconditioned spaces such as attics, crawlspaces, and vented plenums. The 7-inch diameter supports higher airflow capacity compared to smaller branch sizes, making it a practical choice where system design calls for reduced static pressure drop and improved delivery efficiency. Licensed HVAC technicians and sheet metal contractors install this duct as part of forced-air distribution systems.

This flex duct is suited for branch runs in residential forced-air systems and light commercial applications where the duct path travels through unconditioned or semi-conditioned spaces. The R-8 insulation value meets or exceeds energy code requirements in many jurisdictions that have adopted stricter thermal performance standards for duct systems. The 25-foot length accommodates typical branch-run distances without requiring a mid-run connection. The foil jacket provides a durable outer surface that resists puncture and moisture during normal installation handling.

Key Features

• R-8 insulation rating reduces heat transfer in unconditioned spaces such as attics and crawlspaces
• 7-inch diameter supports higher-volume branch runs with lower static pressure loss
• Foil jacket provides puncture resistance and a vapor-retarding outer surface
• 25-foot length minimizes mid-run joints on standard branch runs
• Flexible construction allows routing around obstructions without rigid fittings

Compatibility

Designed as an OEM-style replacement or new-installation flex duct for residential and light commercial forced-air HVAC distribution systems requiring a 7-inch diameter branch duct with R-8 insulation.

Installation Notes

Installation should be performed by a licensed HVAC technician or sheet metal contractor in accordance with SMACNA flexible duct installation standards and applicable local mechanical codes. The air handler and associated electrical circuits must be powered down before connecting duct sections. Flex duct should be fully extended without sags or sharp bends exceeding manufacturer bend-radius guidelines, as compressed or kinked sections significantly increase static pressure drop. Secure all connections with listed clamps and mastic or UL 181B-listed tape — standard cloth duct tape is not an approved closure method for flex duct systems.