Putting foundation vents on our homes is an old fashioned idea. We spend lots of money each month heating & cooling our homes & by having a vented dirt crawl space it raises your monthly electric bill 15% (to 25%) every month, and will lead to a bigger expense with mold removal & rotted wood replacement. It's not the standing water that causes the problem in the crawl space it's the water vapor, also called Relative Humidity, that destoryes the home. Understanding relative humidity & where it comes from and how to control it is what everyone needs to no about. Air is a very efficient way to move water. Air, including humid air, moves easily in and out of spaces. Air brings its moisture content with it wherever it goes. When air is heated or cooled, it's relative humidity changes. Crawl spaces are cool, because the earth is around 55 degress year round. So when we bring in warm humid air into the crawl the air is cooled, and the humidity goes up. Having higher relative humidity causes condesation which causes mold, wood rot, lost energy & brings more pest problems to your home. Please learn as much as you can about your home & how to protect it & your family from mold, wood rot & overall health concerns related to wet moldy crawl spaces.