What Is the Stack Effect?

The stack effect is a term used to describe how air flows through a home depending on the temperature. It’s something that brings about two problems: bringing in contaminated air through the house and causing cold drafts. Crawl space vent covers help prevent the stack effect from taking place because they stop air from outside from entering through the vent.  

• Why Warm Air Rises 

During the day, the air outside is hotter than the air in the crawl space. Because hot air is always traveling to cooler spots, the warm air from outside goes inside the crawl space through the vent. The air in the crawl space, however, is warmer than the air in the home. Warm air is not as thick as cold air, so warm air travels upward. 

The warm air rises and eventually leaves through the chimney or the attic, where it will get warm again. During the summer, hot air rises as soon as it enters the crawl space, but during the winter, it stays there until it warms up a bit. 

• How This Affects You and Your Home 

When the warm air from your crawl space rises and invades your living space, it greatly affects you and your health. As air rises, it picks up all the particles in the area and lifts them up with it. Because the air enters through your crawl space first, it picks up all the dirt and grime in the crawl space. If you have an uncovered crawl space, chances are, it’s humid and a nest for pests such as cockroaches, rats, and termites. Breathing in all that contaminated air is bad for your health, and if you or anyone in your household has allergies, an uncovered crawl space only worsens things. 

Another way the stack effect impacts you is by raising your energy bill. If you have the AC turned on, it will have a much harder time cooling a room down when all that warm air is rising through your home. Because of this, homeowners with uncovered crawl space vents tend to keep the AC on for longer. After covering crawl space vents, you’ll definitely notice a difference in how quickly your AC can cool a room.