Dometic 25' Insulated Flex R4.2 Ducting/Duct - 4"

The Dometic 25' Insulated Flex R4.2 Ducting/Duct - 4" is a premium flexible ducting solution designed for RV, marine, and mobile climate control systems that demand reliable thermal performance and noise reduction. Built to handle the demands of Dometic air conditioning and heating systems, this 25-foot ducting run accommodates installations where standard rigid ductwork cannot be efficiently routed. Whether you're upgrading an existing RV HVAC system, replacing worn ducting, or designing a custom climate control layout, this insulated flex duct delivers the engineered performance Dometic is known for.

This ducting features round wire reinforcement combined with a mylar fabric shell construction, ensuring durability and consistent airflow even in high-flex applications. The standout specification is its R4.2 thermal insulation rating with a substantial 1-inch wall thickness of insulation material, which significantly reduces heat loss or gain as conditioned air travels through the duct run—critical in mobile environments where exterior temperatures fluctuate. The 4-inch diameter is sized to work seamlessly with standard Dometic HVAC outlet ports and distribution networks, maintaining proper air velocity and system efficiency while minimizing pressure drop across the 25-foot length.

RV owners, mobile office operators, and marine vessel crews benefit most from this ducting solution when routing air to cabins, sleeping areas, or distant compartments where rigid ducts prove impractical. The insulation thickness makes it especially valuable in extreme climates—preventing condensation in humid conditions and reducing energy load in high-heat environments. Installation is straightforward with flexible construction that bends around obstacles while maintaining structural integrity, and the mylar fabric shell resists moisture and mildew common in enclosed mobile spaces. Compatible with Dometic's full range of rooftop and under-unit air conditioning systems, this ducting (Legacy # 226600078) is a direct replacement for original equipment or an ideal upgrade component for custom HVAC modifications.