4" x 25' Silver Jacket Flex Duct, R8

Product Overview

The JP Lamborn MHP25R8B-04 Flexible Air Duct is an R-8 insulated air distribution component engineered for residential and light commercial HVAC applications. Constructed with a durable silver vapor-barrier jacket, a fiberglass insulation layer, and a wire-reinforced inner core, this duct delivers reliable airflow and superior thermal performance. It is designed for use in both supply and return air systems, maintaining efficiency and compliance with mechanical, fire, and energy codes.

Technical Specifications

• Model: MHP25R8B-04
• Manufacturer: JP Lamborn (Hart & Cooley)
• Series: Residential
• Product Type: Insulated Flexible Air Duct
• Inside Diameter: 4 inches
• Length: 25 feet
• Insulation Value: R-8
• Outer Jacket: Silver vapor-barrier jacket for moisture protection and durability
• Air Velocity Rating: 5000 fpm (maximum)
• Temperature Range: -20°F to 140°F (-29°C to 60°C)
• Core Construction: Helically wound, wire-reinforced inner core
• Insulation Type: Thermal fiberglass blanket with polyethylene vapor barrier
• Application: Supply and return air distribution in HVAC systems for residential and light commercial use
• Compliance: UL 181 Class 1 Air Duct; conforms to NFPA 90A and 90B standards
• Installation: Approved for use in conditioned and unconditioned spaces; suitable for concealed or open mechanical runs

Professional Notes

Install per JP Lamborn and SMACNA standards for flexible duct systems. Extend duct runs fully to reduce static pressure loss and maintain designed airflow capacity. Support at recommended intervals to prevent sagging or compression of the insulation layer. All joints and fittings must be sealed using UL 181-approved tapes or mastics. Avoid sharp bends or excessive compression to preserve the duct’s thermal and airflow performance characteristics.

Summary

The JP Lamborn MHP25R8B-04 Flexible Air Duct is a 4-inch diameter, 25-foot R-8 insulated duct with a silver vapor-barrier jacket. Rated for 5000 fpm and -20°F to 140°F operation, it provides code-compliant, thermally efficient air distribution performance for professional residential and light commercial HVAC installations.