If you block a crawl space vent it can work well ... of course, include fan systems and are somewhat expensive to buy, beginning at about $100 or higher, depending on how many pieces an individual ...

If you have mold in your crawl space, it's an issue that should be addressed immediately, but is it necessary to dehumidify ...

A dirt floor in a basement or crawl space can be a major source of moisture ... on foot traffic (more foot traffic = thicker), cross ventilation efforts, and humidity levels.