For a long time, people thought open crawl space vents were actually a benefit in a home. The idea was that crawl spaces needed ventilation because the ventilation would help “dry out” the crawl space. In fact, many building codes required ventilated crawl spaces, with minimal exceptions for unventilated crawl spaces.
Although this was a popular idea for many years, it doesn’t hold up to scrutiny nowadays. Because of the different temperatures of outside air and air in your home, open crawl space vents may actually increase the amount of humidity in your crawl space, rather than reducing it. Clearly, it’s not a good idea to leave your crawl space vents open.
The good thing is that there are many ways to return your crawl space to an encapsulated state. JES offers crawl space vent covers that you can add to your vents to avoid the entrance of water, moisture-laden air, or anything else into your crawl space.