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Should I Close the Crawl Space Vents or Leave them Open?

Sealing your crawl space vents is the most sensible thing to do especially in summer when the outside air is dense with moisture.

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While it may take years for people to agree unanimously to close their crawl space vents, the facts remain. An open crawl space vent is bad news for your home. The continuous flow of moist outside air makes it impossible to control moisture inside. Whatever effort you’re to take from there on will be more of firefighting. You can’t compete with nature, so you can guess who will win and who’ll lose. 

For many decades, codes have encouraged homeowners to vent their crawl space. The belief was that venting would help with aeration. It’s still a reason why some people stick with their vents. As positive as it sounds, there’s a price to pay. We strongly encourage you to close those vents. 

open vent problems

Is Venting the Crawl Space A Good Move? 

Summer heat can make your home feel like a furnace. What do you do? Like everyone, you open your windows wide instead of running the air conditioner to bring down the temperatures. This may seem rational, but it’s not. What you’re doing is letting in moist air. When this air sweeps across your cooler floors or walls, condensation occurs. 

The original motive for venting the crawl space was and is good. But what we have a problem with is the reasoning behind it. Venting aerates the indoors, but it also encourages moisture and various problems. You’re better off sealing these fixtures instead of leaving them open. 

What are the Cons of Venting? 

Study after study suggests that crawl space vents are retrogressive and harmful to your home. You’re likely to see their bad sides during summer when the weather is hot and humid. Moisture may accumulate inside and cause you crawl space to get wet. 

Leaving your crawl space vents open reduces the quality of indoor air. More than 50% of the air you’re breathing in your home comes from the crawl space. Assuming your crawl space is 1,200 square feet, you will receive at least 12 gallons of moisture-laden air from the crawl space. 

Mold is never far off in the presence of moisture. Damp and wet conditions encourage mold growth. When mold takes over, it can encourage wood rot and pests. Both can weaken your wooden structures. 

So, your foundation won’t be strong enough to hold the weight of your home. Next thing you know, your home is failing. 

Crawl space air is mostly laden with pollutants and other foreign particles. All these can float into your home and cause respiratory problems. Not only do mold and dust contaminate the lungs, but they also make the indoor air unbreathable. 

Open vents also increase the costs of cooling and heating your home, and here’s why: Warmer air from the outside floats in and displaces the cooler air inside. This displacement creates a stack effect, which results in temperature imbalance. To bring temperatures to the same level, you have to run your HVAC for many hours. 

Take the next steps 

Don’t leave crawl space vents linger for another day. Seal yours with airtight vent covers and encapsulate the crawl space with a heavy-duty 20-mil plastic vapor barrier. Going over the floor and walls, this barrier will effectively lock out moisture. 

We have sealed many vents and can tell you homes that were once moldy, dirty, and stuffy no longer experience those issues. You will spend less energy on heating or cooling and reduce the number of doctor visits. Best of all, your humidity will drop. 

Looking to seal your vents and encapsulate the crawl space? Get in touch with Ohio Basement Systems for a free crawl space repair inspection and quote in Cleveland, OH. We will seal the vents and waterproof this space so moisture won’t bother you.

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