What is the Stack Effect? – Up to 50 percent of the air in your house comes from the crawl space. That is a significant percentage of how much of the air you breathe in your home is affected from just one area. Crawlspaces are perfect environments for undesirable conditions, such as extreme moisture, fungi, and even pests. Learn how these conditions end up rising to the livable parts of your home.
What Is The Stack Effect?
The stack effect is defined as the occurrence when warm air moves upward in a building. This happens in summer and winter but is most pronounced in the winter because indoor-outdoor temperature differences are the greatest. Warm air rises because it’s lighter than cold air. So, when indoor air is warmer than the outdoor air, it escapes out of the upper levels of the building, through open windows, ventilation openings, or penetrations and cracks in the building.
The rising warm air reduces the pressure in the base of the building, forcing cold air to infiltrate through open doors, windows, or other openings. The stack effect basically causes air infiltration on the lower portion of a building and exfiltration on the upper part. Mechanical equipment such as fans and blowers cause the movement of air within buildings and through enclosures, which can generate pressure differences.
The stack effect doesn’t occur just in residential homes; it can also happen within commercial buildings as well.
Stack effect occurs in tall buildings when the outdoor temperature is substantially colder than the inside temperature. Hot air rises, so the warmer, indoor air is buoyant and presses upward to exit the building through a variety of openings in the upper floors. This movement creates negative air pressure in the lower levels of the building and causes the cold outdoor air to be pulled into the building.
The taller the building and the colder the outdoor temperature, the greater the negative pressure on the lower floors. In fact, if not properly addressed, the air in a street level space of a high-rise building could be completely replaced in less than a minute. This same space could take 20 to 30 minutes to warm back up to a comfortable temperature, assuming the doors remained closed, creating an impossible heating requirement to deal with on extremely cold days.
Eliminate the threat of pests, prevent moisture under your home, reduce allergens, and improve the air quality in your home, as well as your energy bill! Inquire about a Crawlspace Encapsulation from U.S. Crawlspace today! Take control of the stack effect in your home today.