I bought a new pvc housing unit from a breeder in my area. It has two doors on the front that swing open and have about a quarter inch of space between them. I believe it is a Zoo Products PVC cage. I'm worried that there isn't enough ventilation. There aren't any vent holes built into the enclosure besides the area around the doors. The snake seems to be doing fine, but I'm not exactly sure how to tell if it's enough.
TL;DR: How much ventilation should there be in an BP enclosure?