Part of the reason that dirt crawlspaces with open vents are a nightmare is because our humidity here in Leitchfield. Our crawlspaces suck in the moist outside air and that air is drawn up through our crawlspaces and out our attics. This means that all that dirt, mold, and yuck is carried in the air throughout our house. It also means that our air conditioners have to work much harder and that costs us more money!