At a home & garden show today, I saw a number of vendors pushing their encapsulated crawl space, mostly CleanSpace brand. In some ways it sounds attractive but they claim you need no vents and no dehumidifier. It seems to me that with no air movement there will be inevitable humidity build up due to small leaks, air conditioning ducts etc. and that the mold problem could be increased rather than eliminated (dark, moist, little to no air movement).
Does anyone have experience with these? Good or bad experiences? If so, how long has it been installed?