Apparently, depending on whether you talk to a Termite Inspector or a Home Inspector or a 'Crawl Contractor' or me or 'The Insulator', you'll get different answers to how to solve your problem.
I live in SE PA. Here, we install crawl vents per 200 sq. ft. (give or take) where the crawl's foundation is poured concrete. In the vast majority of cases, they're unheated (essentially outside.) We don't install fans nor are they 'normally' part of the main house. (We have them but in much, much older homes.)
In the poured crawlspaces, we put in vents w/o fans, when they're part of the outside world. If they're dirt and part of the outside world, we put vapor barriers on them and leave them alone. If they're concrete and part of the inside world, it's just another heated space, and we 'handle it' like we would any other heated part of the house. If it's dirt and part of the inside world, we treat it the same as the concrete inside world EXCEPT we add a vapor barrier. In short, vents are used for unheated crawls, dirt or concrete based on the aforementioned formula.
Here's a recent Post that's still on going. Crawl Ventilation I'll be watching it but it helps with the 'gist' of your problem. For now, my best to ya and hope this helps.
PS: I'll be back on Monday morning but others will be around ...