Forgot about this thread...
Yes, I have central air in the house. But, it's a crappily designed system. It really doesn't run long enough to remove a lot of humidity, especially in the basement, before it cools the house off.
I made a few changes in the basement, and it seems to be working.
Where I have the safe is pretty restricted, so I shut the one door to the back room, opened up a vent over the safe, and put the dehumidifier right there. It seems to have set up a "dry zone" around the safe.
No rust on anything, so I think I'm doing OK.
The DC area is so hot and humid during the summer that, in the days before air conditioning, many European nations classified it as a tropical posting for their diplomats.
In June we had 18 days over 90 deg. F., two days over 100 deg. F, and very high humidity. During the evening hours humidity levels were as high as 75%, during the day it would dip down into the high 50s or low 60s percentage wise.
This whole area is pretty much swamp (DC was a reclaimed bottom land swamp), and we get coastal humidity and Gulf of Mexico humidity.
It's not at all uncommon to have a very hot and humid day with a thunderstorm where there's rain coming down, bright, strong sun, and water vapor cooking off the ground to produce a ground mist, all happening at the same time.
"The gift which I am sending you is called a dog, and is in fact the most precious and valuable possession of mankind" -Theodorus Gaza
Baby Jesus cries when the fat redneck doesn't have military-grade firepower.