Heating, Air Conditioning, Fridge, HVAC/dirty sock syndrome


Robert Currie wrote at 2006-11-15 21:15:52
Humidity has nothing to do with it.  I have over 20 yrs experience in HVAC and am currently a General Manager of a large HVAC company.  I am also a CIE "Certified Indooor Environmentalist"

We live in SE Texas (humidity capitol of the world).  Humidity design is 80% outdoor.

Has only to do with micro organisms that penetrate the pores of the metal in evap coils.  Only very clean coils are typically affected.  Makes no difference if it is a Heat Pump or Gas Heating.  This stuff is like the plague, it knows no boundaries.

No complete cure.  No manufacturer can explain where it comes from.  No studies that I can find tell us what the root cause is.

Could have 3 identical homes side by side and only 1 might ever become affected.

UV lights do not work, despite millions in advertising.  

We have even replaced entire evap coils, only to have it return next heating season.  There are no "constants" or things in common we have found whey trying to figure this out.

It could come from candles,hair spray, or simply blow in from outside.  No one Knows!

It is usually at its worst when we are in between cooling and heating season.  When the evap coils are "wet and dried".  Seems to go away with long periods of "heating" when cold outside or during summer months when coils are wet.

My recommmendation is to have unit serviced by someone reputable who won't try to blow smoke up your butt by trying to sell you a $600.00 UV light that will not work. (I have tried UV lights on 3 different homes and none worked.  Yes, I did refund their money).  

So have system checked and cleaned early in the Fall.  We use a detergent type cleaner mixed with good ol' Lysol in the brown bottle.  It is a disenfectant and will stop it for a while.  Only not 100% effective if we have a long period with back and forth on heating and cooling.

I'm sorry no magic fix, but it may save you a lot of time and money looking for something that is not out there.

Robert Currie CIE, NATE

DSS_sufferer wrote at 2008-02-06 16:19:37
I've been experiencing dirty sock syndrome recently and my installer claims this is something new to him.  Living a little further north, maybe this is possible, especially since heat pumps are not as common, and the incident rate is on the order of 3-5% of installations.  He's been working with his distributor and they tried to clean the coil already, without success.  He doesn't believe this can happen, at least not without visible mold/bacteria.  I've read that coated coils is the only solution to this and there are some coating manufacturers whose products will not adversely affect the heat transfer rates of the coils, thus maintaining their higher efficiencies.

Rob T wrote at 2012-12-14 19:26:35
dity sock syndrome: I have had good success in wilm, nc with "EXODOR" hvac odor treatment. Walex company here makes it. You have to clean coil, pan etc, 1st. Then apply this to coil with high pressure atomizng sprayer(easy). Must do yearly. but i have customers who swear by it.I am not expert hvac, but spent weeks studying & reading anything i could. we just retreated with another brand, mistake. smell was back in 2 days. last time with exodor lasted 1 year. just retreated today. i work customer service at hvac comp here. everyone i did this for is happy so far. really feel for those fighting it. good luck.  

Ron Wharton wrote at 2016-01-27 14:13:21
No reason anyone should pay to have their AC system cleaned for "dirty sock syndrome"

This a know manufacturers defect in the coils and can only be taken care of with new coils. This is per Trane and they say it relates to all manufacturers as there is a 10% failure rate on coils.

And yes, this is mold buildup on the coils as the new heat pump systems do not get hot enough to kill the mold buildup from condensation.

Exodor is only a temporary fix and should be applied FREE by the company that sold and installed your AC system.

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J Cook


With 25+ years experience, I am familiar with residential, commercial, and industrial HVAC equipment including but not limited to boilers, chillers, reciprocating and screw compressors. I am trained in all manners of control wiring.


I currently have three HVAC licenses and Refrigeration license by the State of North Carolina. I have been in this field for over twenty years. I have been a service technician for a contractor and also worked at a state college in the repair and maintenance of steam lines and equipment. I am currently the Building Maintenance Superintendent for a municipality.

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