I live in NC where it is hot and humid all summer and stuff rusts like crazy here. I keep everything in a cheap gun cabinet and I have A tiny dehumidifier inside. Zero problems with rust since and it has to be emptied roughly every other week.
Well, if nighttime is cool enough, a CHE can help. But, for my beardie in the warmer months I use a mini dehumidifier in her enclosure at night- http://www.amazon.com/Ivation-IVADM10-Small-Size-Thermo-Electric-Dehumidifier/dp/B00MQ7T038/ref=sr_1_11?ie=UTF8&qid=1430075225&sr=8-11&keywords=mini+dehumidifier. I place it inside of her enclosure at night and remove it during the day when her lamps take care of the humidity.
I'd be inclined to try this out actually... https://www.amazon.com/Ivation-IVADM10-Small-Size-Thermo-Electric-Dehumidifier/dp/B00MQ7T038/
Only uses 13.5W of power...
If you have a mini dehumidifier, it will pull all the vapor out of the air.
If not, get something like this. http://www.amazon.com/dp/B00MQ7T038 Find one in your budget. Just make sure it's not to small.