Crawl space encapsulation will almost certainly help you lower your energy costs. In fact, some people suggest you could save up to 15-25% in energy costs when you encapsulate your crawl space. It can be more difficult to cool your home when the air is humid, and the same holds true whether you’re cooling your crawl space or the rest of your home.
When you encapsulate your crawl space, you’re removing all ability for moisture to enter the crawl space. When moisture can’t enter your crawl space, it also can’t rise up through the rest of the home. That means you have to use much less energy to condition the air in your crawl space and in the home in general.