Owl gray flex duct Owl-Flex Owl-Flex™ brand Gray Flex Duct Deterioration & Failures

  • OWL FLEXDUCT - Deterioration of Owl-Flex™ brand Flex Duct in Air Conditioning or Heating Systems. Role of UV light exposure & heat in gray flex duct deterioration in buildings. Defective duct products and materials.
  • POST a QUESTION or READ FAQs about deteriorated or lost plastic exterior or interior of certain flex-duct hvac duct brands

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This article explains Owl brand gray flex duct disintegration as an example of defective heating or cooling ductwork materials.

Photo of deteriorated Owl brand gray flex duct and the suggestion of possible UV degradation of flex duct (in addition to heat) are courtesy of Florida home inspector Eric Van De Ven who has reported on several homes with badly-deteriorated flexduct. We include references to product failures by manufacturers of similar flexible duct work products.

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OWL FLEX DUCT - Deterioration - Caused by UV Light Exposure?

Owl gray flex duct Owl-FlexAir conditioning duct system defects include a remarkably wide range of errors, from failure to supply cool air or failure to even circulate air in the building, to health hazards such as use of asbestos material in or on duct work, to very dangerous conditions such as drawing heating equipment combustion gases into the building cooling (or heating) air.

This article explains Owl brand gray plastic-covered flex duct failures that appear as loss of the gray plastic duct covering due to brittleness that appears to be caused by exposure to heat (such as in a hot attic), with references to product failures by several manufacturers of flexible duct work, including ATCO™ Ruber Products, Alloy Systems™, Goodman™ flex duct, Owens Corning™ flex duct, Owl™ flex duct.

We believe that none of these defective flex duct products is currently sold (2013) but both may be found in older homes. Note: not all Owens Corning flex duct products share this defect and disintegration problem.

A Little Owl-Flex Patent History

Owl-Flex gray plastic-covered insulated flex-duct was patented in 1971, US Patent No. 3,606,404, as a "duct to register connection" by John L. McGann and assigned to Intertherm, Inc. in St. Louis MO.

Related patents were cited dating back to 1930. Intertherm, Inc. is a company whose roots date to 1919 ( The company today specializes in providing HVAC systems for manufatured homes.

Intertherm can be contacted at Intertherm Heating and Cooling Customer Service, 8000 Phoenix Parkway, O'Fallon, MO 63368 but we doubt that the modern company nor its parent company Nordyne accepts responsibility for Owl-Flex duct system failures. Intertherm Inc. (the modern company) is a subsidiary of Nordyne Corp. ( who currently holds an extensive range of name brands in HVAC and other equipment and systems.

How to Identify Owl-Flex Gray Flexduct in buildings

Eric Van De Ven shows in the photos below, Owl-Flex is identified by both text and a logo on the duct exterior.

Owl gray flex duct Owl-Flex Owl gray flex duct Owl-Flex

What is the Problem with Owl-Flex and Some Other Flex Duct Insulation Products?

The loss of the protective plastic covering on flex duct poses several concerns including loss of the duct insulation, increased air conditioning system operating costs, and possibly air leaks out (if supply ducts are damaged) or un-wanted attic debris leaks in (if return ducts are damaged), and in-duct condensation in the HVAC system leading to mold and indoor air quality concerns.

Discussing the page top photograph of badly-deteriorated Owl-Flex duct, Mr. Van De Ven had an interesting observation:

I did an inspection yesterday and found some of the Owl-Flex duct work. The interesting thing that the most damaged portions were located near a window, that someone thoughtfully installed in the attic.

Because we argue that if we completely understood any building failure, there would be no coincidences, we speculate that in addition to the role of of high attic temperatures in some gray flex-duct deterioration, the window cited by Mr. Van De Ven may have provided added light and possibly some UV (depending on glass type) and certainly some additional sunlight-generated heat that helped explain why the flex duct was most-deteriorated where light from the window was shining on it.

Photograph of Owl gray fiberglass-insulated air conditioning duct work in a Kings Point, Delray, Florida attic - thanks to Eric Van Der VenThis photo of Owl-flex™ gray plastic-covered, fiberglass insulated duct material shows damaged gray plastic covered flexible ductwork near a fluorescent light bulb.

The photo at above-right, also taken in the same building by Eric Van De Ven shows the brand name on ductwork installed in the building. The photo at above-left identifies the deteriorated duct shown in our page top photo.

Owl-flex flexible ductwork has been the subject of litigation around the sale of a home, including a complaint of "mold" in the air ducts, as shown in this FLEX DUCT LAWSUIT [PDF] document filed in 2009.

As with the Goodman flex-duct problem described at GOODMAN GRAY FLEXDUCT, and also at in hot attic spaces or where exposed to UV light, the Owl-Flex flexible air conditioning duct material disintegrates leaving its fiberglass insulation exposed to also disintegrate, leak, or possibly blow into the building living space.

Does Exposure to a Nearby UV Light Also Cause Gray Flex Duct Damage?

Two common sources of deterioration in plastics are heat and UV light.

UV Light as a Source of Gray Flex Duct Deterioration

Gray flex duct installed (C) Daniel Friedman Eric VanDerVenReally? A fluorescent bulb contains low pressure mercury vapor, a gas that produces invisible ultraviolet light (UV radiation) when the gas is excited by electricity. Phosphorescent coating on the inside of the fluorescent light tube absorbs the UV radiation and converts it to visible light.

According to General Electric, a manufacturer of fluorescent light bulbs,

Regular fluorescent light bulbs used in your home and office do not produce a hazardous amount of ultraviolet light (UV).

Most light sources, including fluorescent bulbs, emit a small amount of UV, but the UV produced by fluorescent light bulbs is far less than the amount produced by natural daylight. (Ultraviolet light rays are the light wavelengths that can cause sunburn and skin damage.)

But bringing up the sun does not address the impact of UV on thin plastic covering flexible ductwork.

UV absorption and polymer degradation occurs when polymers such as polypropylene and polyethylene absorb UV light causing weakening of molecular bonds at weak points in the polymer chain. So since many polymers are degraded by exposure to UV light, and therefore many plastics are damaged and made brittle by UV light, the close proximity to the bulb is a very strong suggestion.

Heat as a Source of Deterioration of Gray Plastic Covered Flex Ductwork

Heat is also a factor in plastic degradation, which may explain why more of the Goodman, Owens Corning, Or Owl type gray flex duct deterioration was in (hot) attics. Wikipedia: "Polymers are susceptible to attack by atmospheric oxygen, especially at elevated temperatures encountered during processing to shape."

Presumably also in a hot attic heat is a well understood factor in plastic deterioration such as plastic covering flexduct.

A UV light also gives off some heat, though usually less than a typical incandescent bulb. So heat from a UV light very close to the plastic duct cover may also be a factor in deterioration.

The hypothesis that gray flex duct deterioration close to a fluorescent bulb is strengthened if the damage was less or absent on the same material where it was more distant from or not exposed at all to the UV light from the bulb, but where otherwise it was of the same age in the same general building conditions (such as exposure to temperatures).

When a flex-duct product has lost its exterior plastic covering the effects are these:

  1. The cost of heating or cooling the building is increased due to lost insulation: because the ducts are no longer insulated from the ambient temperature in the attic or crawl space where they are located.

    For example, an air conditioning duct passing through a hot attic and missing its insulation will be heated by the ambient attic air, delivering warmer air to the living space than is desired.

  2. The cost of heating or cooling the building is increased due to leaks: because damaged ducts are more likely to leak, cooled or warmed air intended for the occupied space may be lost in the attic or crawl space where the damaged HVAC ducts are located.

    In addition we might see these two indirect problems developing:

  3. Increased circulation of fiberglass particles from the duct insulation or from building insulation which may be picked up and blown into the building air supply

  4. Mold growth in the HVAC ducts due to loss of insulation and increased in-duct condensation in some circumstances. See Flexduct Lawsuitat our references below.

Replacement of the heating or air conditioning flexible sections of duct work is required - a significant expense which will be greater if flex-duct needs to be replaced where it passes through inaccessible areas such as finished walls or ceilings.

Notice that not all flex-duct products will fail in this manner and unless you specifically find evidence of this deterioration, replacement of the flex-duct in a building may not be warranted. Where this duct is found in a building it should be replaced.

Below at Technical Reviewers & References we include Flexible Air Duct Installation Manuals, standards, guidelines, and contact information for several flexible air duct manufacturers as well as access to Flexible Duct Performance & Installation Standards provided by the Air Diffusion Council.

List of plastic-covered flexible HVAC duct products that appear to deteriorate in hot spaces like attics

Readers concerned with deteriorating plastic and fiberglass-covered flex duct in buildings should see the duct failure reports listed below.

Rerader Question: Is there or was there a recall or a class action lawsuit against DuPont or Owl Duct?

(July 15, 2015) Anonymous said:

Is there a class action suite against DuPont or Owl Duct? If so how to I participate in it? What does it normally take to replace duct work? Is my house permanently damaged now because of mold? Please help.

I just found out that a house in Florida that I bought in 2013 has Owl Ductwork. There is moisture leaking and the warranty company says it is not covered. The house was built before 1986. My name is Brent Greiner at

22 July 2015 Mary D said:

Were the Gray Owl Flex duct materials ever recalled? And if so, when? Is there a date/year prior to 2009 when the lawsuit was filed that the industry recommended not to use them?



Lawsuit or litigation around Gray Flex Duct failures such as the Owl Duct you mention are cited in the article above.

We have not found documentation of class action ligitation nor a manufacturer's HVAC duct recall for Owl Flex duct.

The cost to replace ductwork depends on where the duct to be replaced is located. If it is accessible the costs are likely to be a fraction of the cost if one needs to open and then close and repair ceilings or walls.

If you are concerned about mold contamination a visual inspection by a competent mold or environmental inspector (of your home) is most important. Don't rely on"mold tests" alone.


I've researched the Owl Gray Flex Duct recall question a number of times in various venues and have never found any reference to a recall nor to an industry-given recommendation against the use of this or any of several other gray flex-duct products that failed in application.

I do not know, but I *speculate* that as the problem of deterioration and disintegration of gray plastic covered flex duct occurred across several product brands, perhaps several manufacturers were all obtaining their plastic duct covering from the same supplier, or were using the same (deficient) product specification for that material.

But in sum, readers looking for a class action settlement, someone to sue, or financial relief are unlikely to find it for gray flex duct products such as Owl Flex Duct.


Continue reading at GRAY FLEXDUCT FAILURES or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.


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