There are advantages and disadvantages to having a crawl space under your home. The advantage, perhaps, a slightly higher house may be more attractive than a house on the floor. Plus, you can make repairs and modifications to plumbing, heating, and electricity services.
The drawback, crawling space is an area that has never been cleaned. Under the vapor barrier the humidity is always 100% so mold and bacteria are always there. Thermitisides, other chemicals, and even mouse droppings may be present, and odors and gases emanating will migrate to the living room of the house unless proper ventilation is installed. Both in the slab or elevated, if there is radon, good ventilation is needed. You can visit the site www.leadingedgeelectrical.co.nz/home-ventilation to know more about the smart vent.
Another technology is to install a dehumidifier in the crawling room. This can reduce humidity, but again will not dissolve or replace stagnant air. Another thing to think about is that a dehumidifier will be expensive to operate. More importantly, using a dehumidifier requires that you close the crawling room tightly. Thus, the quality of home living room air will be reduced because crawling space air is not diluted and replaced with fresh outside air.
Some systems use a dehumidifier (dehumidistat) control to operate the crawl space ventilation fan. These sounds like you’re headed in the right direction. However, the technology is not right. This is why. Suppose the outside air gets worse (wet). Even though the dehumidistat control is in the crawl space, it will quickly recognize this wetter air condition and start ventilation, even though the ventilation will make the crawling room wetter.