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Rockwool insulation in air vents

BobHr | Posted in General Questions on

I was at a home and we discovered that rock wool batts were lining the return vents. Does this pose any concern.

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  1. BobHr | | #1

    I should add the house was built in 1967. This was insulation batts and not a dense insulation board.

  2. Expert Member
    Dana Dorsett | | #2

    With air tight ducts there's zero chance of the system sucking friable rock wool into the system.

    If the ducts leak, there's some chance, but over the past 48 years of service anything that was loose & light enough to get sucked in has already.

    A HEPA class filter on the system would be able to stop anything as large as rock wool fiber bits.

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