If you block a crawl space vent it can work well ... of course, include fan systems and are somewhat expensive to buy, beginning at about $100 or higher, depending on how many pieces an individual ...

With this exhaust fan, you can exchange the outdoor and indoor air, improve room air quality and balance the humidity. Use crawl space vent fan used for exhausting vent radon gas treating wood gas ...

There are two effective ways to seal your crawl space vents. Either install a vent cover for the winter season or have a professional install an encapsulation to protect the space from flooding.