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Question DetailsAsked on 11/5/2013

How do you kill mold in a whole house humidifier system?

We inherited a house and had no idea the humidifier system had a filter(the previous owner didn't either) and due to this the old filter was molded severely. After changing the filter, how do I ensure mold will not take hold again and make sure it's not in all the vents, carpet(doesn't appear to be- but spores are insidious little things)? Is there an affordable DIY way to sterilize the system?

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3 Answers


Any of the centrifugal types make a very pleasant white noise.
Here is one that WalMart has, that is similar to what I have in mind.
Homedics has an ultrasonic model. While I trust that brand, ultra sonic if a frequency of sound that can be irritating, in my opinion.


Answered 6 years ago by bruinsyue


If the filter was molded severely, you will have mold spores throughout the duct system. But then, there are mold spores all over the world, inthe air you breathe, etc - that is why things start molding within a day or two after they get wet.

I know of no do it yourself way to sterilize the entire system - to do that would take a duct system disinfection fogging or ozone treatment as part of a cleaning. However, if the humidifier is maintaining the correct humidity in the airflow (around 40-50%) then you should not get active mold growth in the ducts.

The humidifier itself, if you can disconnect the power and remove the housing, you could disinfect with 50% chlorine bleach solution (1-2 minutes contact time needed), especially in any water retention pan or evaporative surface, being careful not to get any on electrical components or wires.

Answered 6 years ago by LCD


I have this problem as well, the humidifer feed into a condensate pump and it flows up to the upstair kitchen drain, the mold is in the water filter, plastic tubing and inside the condensate pump. I maintain the humidiity at around 30% with the historic winter we've had so far I assume this will be as bad as it's going to get. If you have a MERV8 and above filter on your furnace that will remove at least 70% of the mold spores, a MERV11 will remove around 85%. I wouldnt worry about the mold as long as you change your filters (humidifer and furnace) regulaurly.

Answered 5 years ago by uyebsk

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