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Actual research on Dirty Sock Syndrome?

ventcent | Posted in Mechanicals on
Hello, we are suffering from DSS in our house and have been since Sept. 2020.
My googling of the term leads to page after page of HVAC contractor websites that recite variations of the same industry talking points, all geared towards buying more HVAC equipment, surprise surprise.
Last week we had a UV lamp installed and it had no effect whatsoever.
In December we had a brand new coil installed that was coated on-site with something thats supposed to prohibit mold growth.  No change in the smell then either.
The next thing our HVAC contractor wants to do is install a duhumidifier with fresh air ventilation.  Then maybe a HEPA system.
I have a hard time believing anything is growing on the coil given that its winter and the air is very dry (indoor RH is typically 28 – 30%).  Yet everything I’ve read points to the coil being the cause.
Does anyone know of real impartial scientific research on this matter?
Or if anyone can provide advice on actually fixing this issue, that’d be even better.  

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  1. Jon_R | | #1

    Doesn't have to be the coil. Say you have verified that the smell is originating in the ducts. You could sample duct air at various points to identify exactly where.

    At that relative humidity, it would take substantial cooling (like ducts in mostly unheated space) or some other water source to create enough moisture for mold growth.

    1. ventcent | | #2

      I've been thinking its the ducts for awhile now. My house is 2 stories on slab, all the HVAC stuff live in the vented (soffit and ridge) attic. The downstairs unit has the DSS. Even on a cold 40F day, the attic reaches mid 70s and I've worried that about condensation from nighttime cooling or infiltration getting into the ducts. However, we had a blower door test done which included a duct check and both duct systems were found to be tight, as was the house overall.

      I think there is debris in the ductwork, at the bottom of the chase from the attic to first floor ceiling. Unfortunately, being FlexDuct, its hard to fully clean and hard to snake my industrial endoscope very far into to see.

      I'm now on my 2nd HVAC company looking into this matter, and neither mentioned duct air sampling... interesting.

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