I keep reading about insulating the walls and sealing up the crawl space, I have a few questions. 1 After closing up crawl space, are you heating it? 2 If your not heating it, it is still a cold zone, no? 3 Condensation will occur when warm meets cold, at the floor yes? 4 When a house is sheeted with plywood or osb there a gaps left for airflow and under windows holes are drilled so trapped moisture can get out behind the siding. 5 Many crawl spaces have some walls that are wood frame and were never ment to be insulated, so the vent holes were never drilled. If you end up with any amount of heat in the crawlspace you will have moisture build up against the sheeting and this is a big problem isn't it? 6 When you have any kind of plumbing leak water spill in the house, it will find its way to the crawlspace, are you going to leave it there untill spring.