Homes and buildings aren’t entirely sealed off. At the very least, there’s a ground-level entrance that lets air in. The air that comes in can make the indoors unbearable. How does this air come in? Through the stack effect. Let’s take a closer look by describing the stack effect and show you how it affects your home and the possible remedies.
What Is the Stack Effect?
Air comes in and exits your home continuously through the stack effect, which boils down to the exchange of air. This movement of air creates a vacuum that pulls outside air inside the crawl space or basement and up into your home. Warm air rises through your home and escapes via open windows, gaps in the ceiling, the attic, recessed lights, or ventilation openings. The upward moving air eases the pressure at the bottom of your home and as a result, cold air sneaks in through open windows, doors, or other openings.
In cold weather, the stack effect causes heat to go up together with the warm air. But it’s much weaker due to cooler temperatures. When a cubic of warm air floats up and out, a similar volume of cold air flows in to replace it. The temperature difference between the lower and upper parts of your home will determine the extent of air leaks.
What’s Behind the Stack Effect?
The stack effect happens only when the following conditions exist in a home or building:
Entry and exit point: Air comes into the ground-level entrance and leaves via exit points. Both must be
present for the stack effect to occur.
Rising warm air: The other pre-condition is upward moving warm air, which goes up and creates a vacuum for cold air. Warm air is usually lighter and will go up while cold air is heavier and will settle at the bottom.
Let’s say you have crawl space vents. The air in your crawl space might be warmer or cooler than the surrounding air. If the air is cool, it will settle at the base. But, once temperatures start rising, the air will warm up and rise through the living space before exiting the attic.
Ways the Stack Effect Impacts You
Left unchecked, the stack effect can affect you and your home in many ways. Here’s what will happen if you don’t act:
Increased moisture levels: The stack effect also draws up moisture from the outside and this can make your indoors cold and musty. As moisture builds up inside your home, condensation will become commonplace.
Mold growth and exposure: Whenever the warm air floats up and escapes through the upper parts of your home, it’s immediately replaced by cooler and unpleasant crawl space air. This air has a pulling effect, which is another way to say that it brings with it dusty, mold spores, allergens, and harmful bacteria.
High energy costs: Unregulated airflow will also cause temperatures to swing wildly. Summers may become hot and winters cold. Seasonal changes will force you to run your HVAC for longer than usual. And this translates into higher costs.
Crawl space damage: Your exposed crawl space will also take a beating due to the effects of the outside air on its wooden supports and joists. Both can decay and lose their strength. Your insulation can also get wet and sag.
Unnecessary repairs: Once your crawl space deteriorates, you will have to repair it. This will cost you money. You can avoid repairs by taking preventive measures like sealing the vents and encapsulating the crawl space.
Natural ventilation methods such as air outlets are effective in mitigating the problem. For high-rise buildings or buildings with limited space, mechanical ventilation is the only recourse.
In homes, it also helps to seal up the crawl space with a plastic vapor barrier. What this does is prevent warm-cold air exchange and the related unpleasant effects. Complete Basement Systems can help you encapsulate the crawl space to cut off outside air. Your interior will become comfortable and dry and the air quality superb.
To get started, schedule a free crawl space encapsulation inspection and get a complimentary estimate for the job today.