All current science supports the benefits of conditioned crawlspaces. Current science sayABSOLUTLEY DO NOT VENT! Non-vented or Conditioned Crawl Spaces differ from Vented Crawl Spaces by creating an effective seal without vents, thereby reducing the amount of moisture that can enter your home. Once the seal is in place, and your home complete, conditioned air circulates between your home and crawl space. This constant exchange of air results in an average of 50-55% humidity. With humidity levels controlled, a Conditioned Crawl Space is less likely to have mold and mildew, eliminating several structural and health related issued which can arise years after your home is built. Conditioned Crawl Spaces are gaining popularity as an effective and cost-efficient way to eliminate moisture problems.
Clean Crawl by Cedar Grove.....US Patent No. 7,192,219