This chapter discusses Goodman(TM) Flex Duct failures with references to product failures by two manufacturers of similar flexible duct work products,
Owens Corning(TM) and Goodman(TM). Neither of these products is currently sold but both may be found in older homes.
The master document, of which this is a chapter, describes the inspection of residential air conditioning systems (A/C systems) to inform home buyers, owners, and
home inspectors of common cooling system defects.
GOODMAN GRAY FLEXDUCT - Deterioration in Hot Locations
This Goodman gray flex duct or "flex duct" air conditioning duct work material is a defective product.
In hot attic spaces or where exposed to UV light, the plastic of this flexible air conditioning
duct material disintegrates leaving its fiberglass insulation exposed to also disintegrate, leak, or possibly blow into
the building living space. Replacement of the duct work is required - a significant expense. - Thanks to Jon Bolton for these photos.
of Goodman gray flex duct disintegrating in an attic.
Where this duct is found in a building it should be replaced. When a heating or air conditioning flex-duct product has lost its exterior plastic covering the effects are these:
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.
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:
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
Mold growth in the HVAC ducts due to loss of insulation and increased in-duct condensation in some circumstances.
For another flex duct product that is not as old but which can have similar disintegration problems, see
OWENS ORNING FLEXDUCT
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Thanks to Mark Cramer, Tampa Florida, for assistance in technical review of the "Critical Defects"
section and for the photograph of the deteriorating gray Owens Corning flex duct in a hot attic. Mr. Cramer is a Florida home inspector and
home inspection educator.
Thanks to Jon Bolton, an ASHI, FABI, and otherwise certified Florida home inspector who provided photos of failing Goodman gray flex duct in a hot attic.
Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair
Our recommended books about building design, inspection, and repair, and about indoor environment testing, diagnosis, and cleanup are at the InspectAPedia Bookstore.
"Air Conditioning & Refrigeration I & II", BOCES Education, Warren Hilliard (instructor), Poughkeepsie, New York, May - July 1982, [classroom notes from air conditioning and refrigeration maintenance and repair course attended by the website author]
Carson Dunlop, Associates, Toronto, have provided us with (and we recommend)
Carson Dunlop Weldon & Associates' Technical Reference Guide to manufacturer's model and serial number information for heating and cooling equipment ($69.00 U.S.).
InspectAPedia® Home & Site Map - Building & Environmental Inspection, Testing, Diagnosis, Repair, & Problem Prevention Advice: In-depth research & advice on diagnosing, testing, correcting, & preventing building defects & indoor environmental hazards. Unbiased information, no conflicts of interest.
The Mold Information Center: What to Do About Mold in Buildings, When and How to Inspect for Mold, Clean Up Mold, or Avoid Mold Problems
Environmental Inspection, Testing, & Diagnosis On-Site IAQ, Gas, Air Testing, Mold Investigation, Sick Building Diagnosis, Lab Services, & Remediation Plan Preparation - indoor air quality testing, problem source determination, supporting lab work, written remediation plan addressing removal of environmental and other hazards and prevention of their recurrence.