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Why Close Crawl Space Vents: They do More Harm Than Good

Wednesday, March 16th, 2016 by Holly Richards-Purpura

As the temperatures begin to rise with spring and summer on the way, you might think that ventilating your crawl space will help with airflow and control temperatures under your house. This is a bad idea for several reasons.

This diagram depicts how the stack effect allows air to enter through the crawl space and be

Open crawl space vents create the “stack effect.”  Air in the crawl space is drawn up through the house in an airflow pattern from bottom to top. Whatever is in your crawl space air is in your house and affecting you. For example, if the air vented into the crawl space is damp and wet, the above floors also will feel damp.

You are wasting your money if you open your crawl space vents, because this causes major energy penalties. Cold air will be vented into the crawl space during the winter, causing the above floors to also be cold and for the heating system to work extra hard to create a comfortable atmosphere you desire. The same thing happens with warmer summertime air and overly-taxed cooling systems.

Water intrusion is another common problem caused by open vents. Not only could this cause flooding in the crawl space, it creates a breeding ground for mold and moisture. This is especially true in crawl spaces with fiberglass or batt insulation. Any water or humidity issues will cause this insulation to deteriorate and fail. It also creates unpleasant odors you may smell on upper floors because of the stack effect.

Open vents also are welcome signs and unintentional invitations to outside nuisances like bugs, rodents and other pests. If termites make your crawl space their home, they could do some serious damage to any wooden supports and compromise the structural stability of the house.

How would you like to save at least 15 percent on energy costs and protect your home from pest and water intrusion? Your best solution is to close those crawl space vents by covering them with vent covers.

These attractive plastic covers will not rust, rot or need paint. They permanently attach to the exterior foundation walls with drilled-in fasteners, and have foam insulation and gasket material to completely seal off the outside air.

Vent covers are the perfect complement to the CrawlSeal crawl space encapsulation system that isolates the home from the earth. If you are concerned with the air quality or humidity of your crawl space, we can install the powerful but energy-efficient dehumidifier.

Additional options that keep the outside air out of the crawl space are Crawl Space Doors and the entry well entry well.

If you are concerned with the condition of your crawl space, contact Ohio Basement Authority today to schedule your free, no obligation inspection. Our expert team can help you create a healthier crawl space, and a healthier home.


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