Having an exhaust duct in the sealed crawl space creates negative air pressure inside the house; that pressure must be relieved in some manner, and if no fresh air intake is provided, air will be drawn in from leaks in the envelope, including: fireplace flues, bath and kitchen exhausts, electrical fixtures not properly sealed, and other places.
It occurs to me that this project is built backwards and will lend itself to condensation and moisture penetration. In my mind the insulation should be under the slab and on the exterior of the walls. The ground is going to change temperature and so will the concrete. You don’t wear a coat on the inside of your body....fail.
so, do you insulate a basement from the outside in, or any exterior wall? Nope, you obviously do not understand the science behind a conditioned crawl space. Its been around for some time and without the issues you have concern about.
