{"product_id":"quietflex-4kmr8-insulated-flex-duct-r-8-4-in-25-ft","title":"Quietflex 4KMR8 Insulated Flex Duct R-8 4 in 25 Ft","description":"\u003ch3\u003eProduct Description\u003c\/h3\u003e\n\u003cp\u003eThe QUIETFLEX 4KMR8 is a 4-inch diameter, R-8 insulated flexible duct designed for residential and light commercial HVAC air distribution. At 25 feet per section, it delivers fully lined airflow with a corrosion-resistant steel wire helix core that maintains shape under negative and positive pressure. The outer vapor barrier consists of a fiberglass scrim reinforced metallized film laminate jacket, which limits condensation and heat gain across the duct run. Insulation is made with Owens Corning EcoTouch formaldehyde-free fiberglass, rated at R-8 thermal performance. HVAC installers and sheet metal contractors are the primary trades who handle this product.\u003c\/p\u003e\n\u003cp\u003eThis flex duct is suited for supply-air branch runs in forced-air heating and cooling systems. Common applications include attic installations, crawlspace runs, and unconditioned space routing where higher R-value insulation is required to meet energy codes. The R-8 rating makes this duct appropriate for climate zones with stricter duct insulation requirements under IECC or Title 24 standards. It ships in both box and bag packaging configurations depending on the order quantity.\u003c\/p\u003e\n\u003ch4\u003eKey Features\u003c\/h4\u003e\n\u003cul\u003e\n  \u003cli\u003eR-8 insulation value for high-performance thermal protection in unconditioned spaces\u003c\/li\u003e\n  \u003cli\u003eCorrosion-resistant steel wire helix maintains duct shape and supports airflow integrity\u003c\/li\u003e\n  \u003cli\u003eOuter vapor barrier jacket uses fiberglass scrim reinforced metallized film laminate\u003c\/li\u003e\n  \u003cli\u003eUL Listed to UL 181 and CUL S110 for use in the US and Canada\u003c\/li\u003e\n  \u003cli\u003eComplies with NFPA 90A and NFPA 90B standards\u003c\/li\u003e\n  \u003cli\u003eGreenGuard Gold Certified for indoor air quality\u003c\/li\u003e\n  \u003cli\u003eMade with Owens Corning EcoTouch formaldehyde-free insulation using 99% natural materials\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch4\u003eCompatibility\u003c\/h4\u003e\n\u003cp\u003eDesigned as an OEM-style flexible duct section for residential and light commercial forced-air HVAC systems requiring 4-inch diameter insulated branch duct with R-8 thermal performance.\u003c\/p\u003e\n\u003ch4\u003eInstallation Notes\u003c\/h4\u003e\n\u003cp\u003eInstallation should be performed by a licensed HVAC technician or sheet metal contractor in accordance with SMACNA flexible duct installation guidelines and local mechanical codes. Shut down the air handler and verify the system is de-energized before connecting or modifying duct sections. Support hangers should be spaced per manufacturer and code requirements to prevent sag, which increases static pressure and reduces airflow efficiency. Avoid sharp bends that compress the inner liner, as this restricts airflow and reduces effective R-value at the bend.\u003c\/p\u003e\n\u003ch4\u003eTechnical Specifications\u003c\/h4\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eDiameter\u003c\/strong\u003e: 4 inches\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eLength\u003c\/strong\u003e: 25 feet\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eR-Value\u003c\/strong\u003e: R-8\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eListings\u003c\/strong\u003e: UL 181, CUL S110\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eStandards Compliance\u003c\/strong\u003e: NFPA 90A, NFPA 90B\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCertification\u003c\/strong\u003e: GreenGuard Gold\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eInsulation Material\u003c\/strong\u003e: Owens Corning EcoTouch formaldehyde-free fiberglass\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eVapor Barrier\u003c\/strong\u003e: Fiberglass scrim reinforced metallized film laminate\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eHelix Material\u003c\/strong\u003e: Corrosion-resistant steel wire\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch4\u003eStandard Information\u003c\/h4\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eBrand\u003c\/strong\u003e: QUIETFLEX\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eManufacturer Part Number\u003c\/strong\u003e: 4KMR8\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"QUIETFLEX","offers":[{"title":"Default Title","offer_id":51344337568050,"sku":"4KMR8","price":90.43,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0270\/4519\/9983\/files\/310552779.jpg?v=1782033557","url":"https:\/\/voomisupply.com\/products\/quietflex-4kmr8-insulated-flex-duct-r-8-4-in-25-ft","provider":"Voomi Supply","version":"1.0","type":"link"}