I have the same problem here in coastal AL. Heat & high humidity are my biggest issues. I have a partially underground storm shelter made of concrete-filled cinder blocks & concrete floor but need to do some revisions since I don’t have the correct airflow needed (after watching Danny’s YT vid showing his proper air flow ventilation system). I also need to seal the concrete walls/floor since they are porous making it a moisture collector which defeats my purpose & adds to my problems. Now funds are an issue to correct both of those problems with the costs of everything skyrocketing like they are. I have used a box fan & a dehumidifier that helps but I’m looking for long-term solutions for the future when electricity may or may not be available or affordable.
My storm shelter is built in the side of a hill that faces & slopes to the west so the door & part of that wall is exposed & why I call it a partially underground storm shelter. It is only covered with dirt on the outside wall about 2/3rds up due to the slope of the land. ANY SUGGESTIONS FOR IMPROVEMENTS?