Does your home have a whole house humidifier on your furnace?  If you do then you should read this article.  I found a reservoir whole house humidifier on a furnace while performing a home inspection in Wilmette, Illinois.  Humidifiers are systems that run water through them while air from the furnace passes through to add moisture to the air.  Mold is known to breed in humidifiers along with other systems in a home. There are two types of whole house humidifiers that can be installed on a furnace supply duct.

  • Pad filtered whole house humidifiers allow the bypass of warm air through the filter of the humidifier which attracts moisture to the warm air.  This air is circulated throughout the home through the duct system of the home.  These types of whole house humidifiers are not known to have high counts of mold.
  • Reservoir whole house humidifiers have water in the bottom of the humidifier where a fan turns with filters on it.  The warm air passes through the filters and the moisture is added to the warm air.  These whole house humidifiers are known to breed mold because of the standing water in the unit.

Both of these types of whole house humidifiers are good for the purpose they are intended for.  They both should be cleaned with dish soap and water to clean out any possible mold growth.   These units should be cleaned annually or replaced every three years to prevent mold breeding.  If regular cleaning of the humidifier the possibility of mold in the ducts will be diminished greatly.  Replacement of a whole house humidifier should only cost $275.00.

Unfortunately, the Wilmette home inspection came up with moist air that was found with hygrometer and surface mildew that I felt that my clients should know what it was.  I suggested a mold inspection for my clients in their new home in Wilmette, Illinois.

I performed a mold air test, a swab sample mold test on the ducts from that the furnace that had a humidifier that happened to have a large amount of mold in it.  The mold inspection in Wilmette came up positive with Stachybotrys which is sometimes called “Black Mold”.  The ducts from the furnace were the area that had evidence of Stachybotrys mold in it and I suggested that the ducts be cleaned by a professional HVAC contractor that had experience with Mediation of mold in ducts.

As you can see mold can come and live anywhere in your home.  My clients from the Wilmette mold inspection were amazed that the mold would be living in the humidifier and contaminate the ducts and rest of the home when in use.  If you have questions about mold and where it can live please contact me at ~ The Mold Inspector or 312-961-4228.

Thanks for stopping by and stay safe.

Jim Kolke 

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