The Stack Effect

The stack effect refers to the airflow pattern in a house from bottom to top, like a chimney. Air enters at the bottom, rises through the structure, and is expelled through the top. It all has to do with air pressure. Air flows from areas of high pressure to areas of low pressure. When there is a greater difference between indoor and outdoor temperatures, the more significant this airflow becomes. (Source: Fine Homebuilding) 

To get a better understanding of the stack effect, it might be beneficial to see it in action. While you can’t see airflow, there is a great demonstration of the stack effect in a YouTube video from the Cold Climate Housing Research Center titled “Your Nothern Home: Stack Effect.”  

More than half the air you are breathing inside your house comes from the crawl space. So, whatever is in your crawl space – such as mold and high humidity – also is in the air circulating throughout the rest of the house and affecting your living environment.