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  1. #1
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    Jul 2013
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    Default Attic/insulation smell coming through central a/c and in through bath fan.

    There is strong attic/insulation smell coming through central air conditioning and in through bathroom fan after unfaced insulation installed over all the attic floor. Smell is also now in areas of the second floor of our colonial.
    No has been able to help fix this problem.
    I have asthma and this is a real problem, PLEASE HELP!

  2. #2
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    Jul 2010
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    Default Re: Attic/insulation smell coming through central a/c and in through bath fan.

    You need to check your vents in the attic. I won't be surprised if you found a messed up connection, where attic air can enter the vent.

    Also: where is your A/C unit (furnace, exchange and coil) located? In the attic, garage or its own closet?

  3. #3
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    Default Re: Attic/insulation smell coming through central a/c and in through bath fan.

    Quote Originally Posted by dj1 View Post
    You need to check your vents in the attic. I won't be surprised if you found a messed up connection, where attic air can enter the vent.

    Also: where is your A/C unit (furnace, exchange and coil) located? In the attic, garage or its own closet?
    Thank you for the reply, the a/c unit is in the attic.
    To be specific the smell that is coming through the a/c ducts is the sour smell from all the unfaced insulation.

    I will have to move lots of insulation, the whole floor and all the silver flex a/c pipes are covered with the new insulation.
    We even taped plastic over the louvers of the whole house fan thinking this was a possible entry point, but the smell remains.

  4. #4
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    Jul 2013
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    Default Re: Attic/insulation smell coming through central a/c and in through bath fan.

    The plot thickens:
    We fixed 2 bathroom exhaust fans that had been venting into the attic.
    When both units were installed initially, they were individually vented straight to the attic with silver flex pipe for a week or so. There was no smell when using the bathroom fan at all.

    Next, the contractor connected both flex pipes to a single hard pipe and vented that pipe outside.
    He then put an additional layer of fiberglass insulation covering the whole attic floor.

    This is when the "attic" smell started coming in the master bathroom.

    We also just had soffitt vents and a ridge vent installed too.

    Is this crazy or what?

  5. #5
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    Default Re: Attic/insulation smell coming through central a/c and in through bath fan.

    There is a possibility that the contractor disconnected a connection while doing his job, by mistake.

    Connectors and vents are secured by tape (duct or aluminum) or with a plastic tie. Not very strong when someone is crawling back and forth around the attic.

    Another place to check: the connections around the cold air exit(s) from the unit.

  6. #6
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    Jul 2013
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    Default Re: Attic/insulation smell coming through central a/c and in through bath fan.

    Quote Originally Posted by dj1 View Post
    There is a possibility that the contractor disconnected a connection while doing his job, by mistake.

    Connectors and vents are secured by tape (duct or aluminum) or with a plastic tie. Not very strong when someone is crawling back and forth around the attic.

    Another place to check: the connections around the cold air exit(s) from the unit.
    Thank you, we have an a/c company coming tomorrow. I will ask them to check all those points you mentioned.
    The smell from the new insulation is so strong. We were hoping it would have dissipated by now (2 months).

    It's now 82 degrees in the house and my family is begging me to turn on the a/c. My concern is that the strong chemical smell could be very dangerous, besides we could be possibly inhaling fiberglass.
    Am I over reacting?

  7. #7
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    Jul 2013
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    Default Re: Attic/insulation smell coming through central a/c and in through bath fan.

    We have identified the smell:
    CertainTeed unfaced R-30, placed a call to the company and was told the smell should have dissipated by now.
    Waiting for someone to call back to resolve this issue.
    I will keep everyone posted.

  8. #8
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    Jul 2013
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    Default Re: Attic/insulation smell coming through central a/c and in through bath fan.

    This has been an interesting thread -- I have a similar (not identical) problem in my house. Just finished renovating and moved into an old townhouse, and installed air conditioning in the process --- a split system for some locations, and a plenum return system for two other locations. Different systems simply because of the challenges of running pipes through brick retaining walls -- better to find other solutions, or so we thought. The result is we are getting "old smoky air" blowing through the locations that are running on the ducted / plenum system (the locations using the split systems are fine -- albeit with the reading I have now done I realize that they are probably too powerful for their locations, because the rooms cool so fast that the dehumidifying never kicks in and the rooms are damp. So I am guessing we can up the temperature slightly to compensate for that?). As soon as I turn the air on, the rooms fill with this awful stale smoke smell. Reading the above comments, I see that a first step will be to bring in the AC company and investigate whether the ducts need to be better insulated, whether anything is "broken" inside the walls, etc. but that seems like a really big and messy job.

    Any other thoughts from readers on this?

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