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Crawl Space Vents: Should They Be Opened or Stay Closed?

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Over the years, people have been venting their crawl spaces to promote air circulation in their homes.
Local codes required crawl spaces to have venting from the outside. They believed these fixtures would facilitate air movement, which would cool the living space in the heat of summer.

Nobody questioned the logic behind vents. All they knew is venting would help stop moisture buildup and prevent any damage associated with it. But new studies show these fixtures do more harm than good to your home.

open crawl space vents

What Do Local Codes Say?

Local codes say venting the crawl space is a good thing. But it also gives you the option to shut them. So, builders and homeowners can decide whether they leave their crawl spaces exposed or seal and condition them. Regardless of which route you take, you will have to meet certain conditions. We advise you to shut your vents as you won’t be able to control moisture if they stay open.

Are Crawl Space Vents Really Useful?

Picture this. Outside temperatures in your home are soaring. You have turned on your HVAC unit to cool the living space, and you have managed to lower the internal temperatures. You turn it off and swing open the windows. What happens? Warm, moist air flows in. When this air comes into contact with cooler walls or floors, it causes condensation. Mirror this to your vented crawl space.

Even though venting is mandatory in many areas and the intention behind it noble, it doesn’t change the fact that the logic is faulty. Venting propagates moisture, the very thing it’s supposed to address. Covering the vents on the crawl space will make your home safer and healthier.

Encapsulating the crawl space and conditioning is the right thing to do. This way, you will beat the moisture trap and allow air to circulate within this space.

The Downside of Crawl Space Vents

Numerous studies show crawl space vents are harmful to your home in many ways. First, they let in moisture during hot and humid summer months. When the moist air comes into contact with cool crawl space surfaces, condensation occurs.

More than 50% of the air that flows into your home originates from the crawl space. A crawl space measuring 1,500 square feet can generate up to 15 gallons of moisture. When this air rises into your home, it can cause various problems and force your HVAC to work extra hard.

Another problem with venting the crawl space is it can lower the quality of air inside your home. Upward moving air can bring with it dust, pollutants, mites, and mold spores. These microorganisms will make the air stuffy, unbreathable, and toxic. If you or your loved one has asthma, their situation could go from bad to worse. This could result in more hospital visits.

Condensation can instigate wood rot, which might weaken supporting structures like joists. This can compromise the structural integrity of your home and set the stage for expensive repairs.

As well as raising moisture levels, crawl space vents also increase heating and cooling costs around the home. The air that moves in creates a stack effect, which creates an imbalance in temperature between the living space and your crawl space. To harmonize the temperatures between both spaces, you have to run your heater or air conditioner for a considerably long time.

Passive moisture can also dampen the crawl space and create conditions that are favorable for mold and mildew. Pests escaping the outside heat will also find a place to quench their thirst and breed.

Seal Vents for a Healthier Home

Want to enhance the energy efficiency, air quality, mold resistance, and structural integrity of your home? Seal crawl space vents with vent covers. Denver, CO, homes with sealed vents outperform their counterparts with unsealed vents. Best of all, encapsulated crawl spaces remain drier than those which are vented, with relative humidity staying below 60 percent in hot summer.

If you would like to seal, encapsulate, and dehumidify your crawl space, get in touch with the professionals at Complete Basement Systems. We provide free crawl space repair inspections and quotes for the installation of lasting solutions that help keep your crawl space moisture-free and mold-free for many years.

Serving Greater Denver area, Colorado Springs, Eastern Colorado, and parts of Nebraska and Wyoming

Colorado Springs, CO

707 County Line Rd.
Palmer Lake, CO 80133

Denver, CO

4686 Ivy St
Denver, CO 80216