I have no experience with gun safes.......Growing up my dad kept his "extra guns" locked in the closet. I have an old gun safe in good condition (no rust, ect.) that I am about to refurbish (paint, change locks, add shelves, ect.). I live in Fl....... Do I NEED a dehumidifier in it? Right now I keep my firearms in my closet and they are free from rust. Currently we live in an older mobile home and it is rather drafty and not at all "air tight" so our A/C unit will not really help much in keeping out the humidity. However, the guns are doing fine in my closet, so, wouldn't they be fine in my safe without a dehumidifier?