What is the advantage of a sealed crawlspace?

A sealed crawlspace is like a "mini basement". It saves energy and contributes to healthier indoor air in the living space. A sealed crawlspace has no vents, the foundation walls are insulated, the ground is covered with thick plastic sheeting and the access door is insulated and weatherstripped. The floor of the living space is not insulated. The crawl remains dry because there are no vents to the outside and the ground moisture is sealed away. Therefore the area is not conducive to mold growth. There is no condensation from the HVAC ducts in summer because no warm outside air is moving across ducts carrying cold air. Again, this promotes a dry crawlspace not conducive to rot, mold and mildew. A small amount of conditioned air is delivered to the crawlspace area from the HVAC system creating positive pressure in the crawlspace. The positive pressure prevents air from the crawlspace being drawn into the duct work and delivered to the living space. Crawlspace air remains in the crawl ...  more