Model # F8IFD8X300

Internet #202562741

Store SKU #812305

Store SO SKU #1000684564

Master Flow 8 in. x 25 ft. Insulated Flexible Duct R8 Silver Jacket

Master Flow

8 in. x 25 ft. Insulated Flexible Duct R8 Silver Jacket

$4695 /each
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Frequently Bought Together

Product Overview

The Master Flow 8 in. x 25 ft. Insulated Flexible Duct R8 Silver Jacket is used in standard Heating and Air Conditioning (HVAC) systems and some venting applications. The duct has R8 insulation which contains 50% more insulation than the standard R4.2 product. This additional insulation provides greater thermal efficiency to save energy. The product is also covered in a heavy duty, silver jacket for durability. The duct is ETL listed, meeting the UL181 standard.

  • R8 fiberglass insulation for greater insulating power
  • Flexible duct is convenient for use in multiple applications including heating and A/C systems and some venting
  • Oversized core to connect quickly and easily to standard sheet metal fitting
  • Galvanized core wire for greater corrosion resistance vs. non-galvanized wire
  • Duct can be cut to length as needed
  • Insulated duct features a maximum temperature rating of 200°F
  • Always install per instructions and seal using approved mastic or sealant (or approved tape)

Info & Guides

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Product Depth (in.)
Product Diameter (in.)
8.0 in
Product Height (in.)
Product Length (in.)
300 in
Product Width (in.)


Silver Jacket
Insulation R-Value
Insulator material
Maximum air flow (CFM)

Warranty / Certifications

Certifications and Listings
2-UL Recognized,ETL Listed

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Customer Questions & Answers

Installation over existing hard duct

Can this product be safely installed over existing hard ductwork? I am wanting to use it to insulate an existing duct in a crawlspace.
Asked by: Patrick
I haven't tried it for a long length but the insulation sleeve easily fit over the section of duct that I pulled it over. I think that it can work if you just take out the core.
Answered by: debuda
Date published: 2016-04-16

Does this product meet California / San diego building code

Asked by: Woody
This product meets all of the national and state codes. Individual city codes will have to investigated individually. Please call Technical Services at 800-211-9612, M-F 8A-5P EDT, for additional information.
Answered by: Master Flow
Date published: 2016-06-17

How much dose this bag of flex weigh?

Asked by: gr
one box of 8" flex weighs approximately 18 pounds. Please call MasterFlow Customer Care at 800-755-9392, M-F 8A-5P ET for any additional information.
Answered by: Master Flow
Date published: 2016-01-27

what is the interior duct wall made of?

what is the interior duct wall made of?
Asked by: atticman
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Customer Reviews

8 in. x 25 ft. Insulated Flexible Duct R8 Silver Jacket is rated 4.9 out of 5 by 8.
Rated 5 out of 5 by from Good product... Good product
Date published: 2017-05-16
Rated 4 out of 5 by from It's Insulated Duct. What can you say about insulated duct? It is used in homes starting at the furnace plenum. Wish that weren't true. In many cases it doesn't need to be insulated since basements are often finished.In my opinion, the length should be limited to 15 feet by code in conditioned spaces but no one seems to have a clue about hard piped duct anymore in residential and not all the pieces needed are sold by the Home Depot to do that kind of work properly.. One big negative is that people crush the insulated flex duct to get around some clearance issue where rectangular hard duct would solve the problem. Then they wonder why the room gets hot or cold. So the product is okay and the insulation seems to be good quality (and is now thicker and more effective in attics). No reason not to buy it. Make sure you connect it properly with tie wraps in addition to foil tape and also one or two screws through the tie wrap to make it even better. That is what folks do in commercial work. And consider "saddles" and the correct strapping to prevent restrictions where the duct sags.
Date published: 2015-03-24
Rated 5 out of 5 by from great product and easy to use Recently bought this and it was easy to install. Before using this product there was an aluminuim pipe and as soon as I installed this in the attic for a return vent, the HVAC unit was working less and the tempreture inside the house was dropping mich faster. Worth spending the extra $16 to get the R8 silver jacket.
Date published: 2016-06-06
Rated 5 out of 5 by from Home Owner DIY Product arrived quickliy via UPS and was relatively simple to intall as a non-contractor DIY fix.
Date published: 2016-05-22
Rated 5 out of 5 by from Exactly as expected Great ductwork, exterior sheath is very strong, and stood up to prodding into place with a broom stick no problem. Used this along with airtec / rectorseal diffusers to install jump ducts to solve an hvac pressure relief issue in the master bedroom. Didn't want to undercut the door due to privacy. This ductwork & those diffusers made it a diy project & saved me hundreds over the quotes I got.
Date published: 2012-03-27
Rated 5 out of 5 by from great insulation Came in ahead of time.looks like a quality product
Date published: 2011-11-22
Rated 5 out of 5 by from works great Works great keeps a great air flow from one room to the next.
Date published: 2014-06-18
Rated 5 out of 5 by from this product has great features great product and quality I recemend easy to work with
Date published: 2012-10-03
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