The first is an exhaust fan that fits into a traditional foundation vent opening (8" x 16"). This fan is rated at over 300 CFM and is ready to be plugged-in. The fan is equipped with a built-in GFI for safety protection. You can view more about this new crawlspace fan by clicking HERE The International Residential Building Code Section R408 requires ventilation for both vented and unvented crawlspaces.
The second is a Crawlspace Humidistat or Humidity Controller. The Controller turns a fan on when humidity rises above a pre set limit. Usually set at 50% humidity since mold will not grow when the humidity is less than 50%. View more information about this Humidistat by clicking HERE.