Air Mixing: What Is It and How It Affects Your Home

Many homeowners (I’d bet most) know their crawl space is nasty, so they never go down there. They shut it out of their “often visited places in my house” list, and shut it out of their mind like it doesn’t exist. Hey, if I don’t go down there, what do I care? Right? Wrong. Way Wrong.

The house is one building. It operates as a system. You can’t have one part of the building that is sick and another part that is healthy. You can’t rationalize that since you never go in the crawl space you aren’t affected by it. Why? Air mixing.

This stack effect creates an airflow in your home from bottom to top. Air from the basement is drawn upward into the first floor, and then to the second floor. Building scientists say that up to 50% of the air you breathe on the first floor is the air that came from the crawl space. If you have hot air heating with ductwork, the air mixes even more thoroughly throughout the house.

Therefore, whatever is in your crawl space air is in your house and affecting you, whether or not you spend any time in the crawl space. If there is high humidity downstairs, there is higher humidity upstairs than there would be otherwise. If there is mold in the crawl space, there are mold spores upstairs. If there are damp odors in your crawl space…you get the idea.