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Home Improvement--General/hvac and fiberglass duct insulation


I recently had a new central a/c installed in my Florida condo. The handler is a pancake unit and when the installer was soldering joints, he burned the surrounding fiberglass insulation. He had not told me about this and I discovered it when turning on the a/c and the condo was filled with a terrible odor! He agreed to replace the 35 year-old charred fiberglass with new fiberglass,saying he has to go about about 3-4 inches into the duct. For health reasons I am concerned about the loose fiberglass now being in the fan and vents. Is there a way to prevent the fiberglass from getting into the air quality? What safety precautions should I take before, during and after the replacement? Should the installer clean the fan system as well?  I would appreciate any suggestions you might have.


The contractor should thoroughly clean the work area around the repair, removing any visible loose particles, and gently vacuum with a soft brush as well.  You need to realize that fiberglass duct board (this product has a rigid fiberglass interior) is not the best choice for optimal air quality.  It can shed fiberglass particles over time, it can't be properly cleaned without damaging it, and it traps more dust than smooth metal duct.  I assume that your system has a high-efficiency filter, which is important for removing larger dust particles.  

Without seeing the system and the work area, I can't give more specific advice.  If you can send photos that would help.

Steve Major  

Home Improvement--General

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Steve Major (Owner - Major Design Group)


I can answer any questions regarding the design and execution of home improvement and remodeling. This includes trade-specific questions (how-to) in all major building trades: framing, foundations, site prep, electrical, HVAC, plumbing, water treatment, interior finishing, trim & cabinetwork, exterior finishing, roofing, siding. PLEASE indicate your state or region, so I can provide the best possible answer. PLEASE provide photos whenever possible.


30 years experience in home improvement design and construction, all hands-on, including the construction of dozens of single-family homes and hundreds of remodeling projects in the northeastern US.

Author: "Architectural Woodwork - Details for Construction" published by Van Nostrand Reinhold (now Wiley).

BS -- Cornell University

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