What is the Stack Effect?

The stack effect is something that affects most homes. Your crawl space plays a big role in how the air moves within your home, which also affects the quality of the air you breathe.  

• Hot Air Rises 

In most homes, air comes in through an opening in the crawl space and exits through an opening in the attic or chimney. Hot air is less dense than cold air, thus it weighs less. Because it weighs less, it rises upward through the house until it leaves through the exit. The reason the air outside enters through the crawl space in the first place is that air will always try to go toward colder areas. The air outside is warmer than the air inside the crawl space, so that’s where it travels to and that’s how it gets in there in the first place. 

The speed at which this occurs depends on the weather. If it’s warm, the air in the crawl space will travel upward toward the house as soon as it enters. If it’s a bit colder, the air will stay in the crawl space for a bit until it gets warm enough to rise.  

• How This Affects You 

The problem with the stack effect is that homeowners breathe in the air particles brought into their homes from the outside. The hot air that rises carries with it the dust and particles from, not just the streets, but the crawl space itself too. If the stack effect is going on in a home with a crawl space that has yet to be waterproofed, the air is causing serious harm to the inhabitants of the household. 

Not only does this kind of airflow affect your health, but it also affects your wallet. In the summer, all the hot air that travels from the crawl space to your home makes it harder for the AC to cool the room. You would need to have it turned on for longer periods just to reach a decent temperature, something that can be avoided with encapsulation.