March 21, 2012

Dear JES: Help! I Have High Indoor Humidity!

Dear JES: 

I have incredibly high humidity in my home - 70%. I've had all of my windows replaced and insulated the living areas of my home to combat this but to no avail. However, I've read that my crawl space could be the reason why I have such high humidity and electric bill. 

What do I do to fix it? 

- Ed T., Suffolk, VA


Dear Ed,

You're right. Your crawl space could be contributing to your indoor humidity and higher electric bills. And it all starts with an unsealed crawl space.

Open vents and loose doors let the warmer outside air into your crawl space. When the warmer outside air mixes with the cooler crawl space air, humidity forms. Then add in dirt floors which retain moisture and you have a recipe for some serious crawl space humidity.

You probably already know that mold thrives in high humidity. But did you know that the air in your crawl space makes its way up into the living areas of your home?

It's true. All of the air, and airborne particles like mold spores, are cycled through your home courtesy of the Stack Effect. So if you have crawl space humidity and mold you'll also have humidity and mold in the living areas of your home.

The best way to get rid of crawl space humidity, and as a result indoor humidity, is to encapsulate your crawl space. To do this you'll need to completely separate your crawl space from the outside elements: sealing off all doors and vents, and covering the dirt floor and walls with a thick vapor barrier, like CleanSpace. And finally conditioning the space with a dehumidifier to ensure that moisture levels remain low.


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