I am researching what to do with my crawlspace. It is very dry under my house, but I need to redo the insulation as it has been in place since the 70's and is hanging etc. I am looking at the crawlspace liners etc and all those installers close off the vents. It got me to wondering if I just replace the fiberglass insulation, should I seal off these vents as it allows the high humidity air under my house in the summer. These vents are fixed open as they were never used by the previous owner and I cannot get them to close manually. I live in coastal NC and it gets very humid in the summer. The winter months are low humidity, so no issue there.