Thermaflex 52304000001 Insulated Flex Duct 4in X 25ft R8

Product Description

The THERMAFLEX 52304000001 is an insulated flexible duct section rated at R8, designed for low-velocity air distribution in residential and light commercial HVAC systems. Measuring 4 inches in diameter and 25 feet in length, this flex duct features a black poly outer jacket that resists moisture and UV degradation in attic and crawlspace environments. The R8 insulation value meets current energy code requirements in many jurisdictions, reducing heat gain and loss between the air handler and the supply register. It ships boxed as a single unit and is part of the Thermaflex KP series. HVAC installers and sheet metal mechanics are the primary end users for this product.

This flex duct is suited for branch-run supply applications in forced-air ducted systems, including gas furnace, heat pump, and air conditioning installations. It is commonly installed in residential attics, dropped ceilings, and crawlspaces where a flexible transition between rigid ductwork and a ceiling or wall register is required. The 25-foot length provides enough run for most residential branch applications without requiring a mid-run connector. Installers should avoid excessive bends and keep the duct fully extended to minimize airflow restriction.

Key Features

• R8 insulation rating meets current energy code minimums for many climate zones
• 4-inch diameter by 25-foot length suits standard residential branch duct runs
• Black poly outer jacket provides moisture and mechanical protection in attic and crawlspace environments
• KP series construction engineered for low-velocity supply air distribution
• Boxed single-unit packaging protects the duct during jobsite storage and transport

Compatibility

Designed as an OEM-style replacement and new-installation flex duct for standard 4-inch collar fittings used in residential and light commercial forced-air HVAC systems.

Installation Notes

Installation is performed by licensed HVAC technicians or sheet metal mechanics. Power down and lock out the air handling unit before connecting or disconnecting duct sections. Secure both ends with approved draw bands and UL 181B-listed tape or mastic per local mechanical code requirements. Avoid sharp bends and compression of the insulated jacket, as doing so reduces effective R-value and increases static pressure drop across the run.