This is the conclusion of a University of Illinois Building Research Council study.
Vents can introduce more moisture than they allow to escape.
In warm weather the air in crawl spaces is usually cooler than the outside air. The incoming air will be cooled to the point that the moisture in it will condense on cool crawl spaces surfaces. The situation is even worse if air conditioning is running in the home above the crawl space. This will mean that the floor above will be one of the cool surfaces on which condensation Back to 'Moisture Problems' Index You are the 5116th access to this page.