[bobfl]

The big problem is preventing mold in the house. This was a big surprise for us when we came to Florida. Never was a problem up North in RI.
The Humidistat is used to control operation of your airconditioning system by only running it when humidity reaches a set point. The temperature, not being controlled, will normally go higher than usual when running like this but since you are not there it really doesn't matter. If you were to set the thermostat to say 8o degrees without humidity control you could get into a situation where the temp was 79 degrees and the humidity was 85%. This would not be a good thing! They tell me that mold will begin to form above 70%. I set my humidistat to 60% and thermostat to 70 degrees. This works because they are wired in series. In essence the thermostat is always calling for the air to come on but the humidistat will only allow it to come on if humidity exceeds 60%. I have done this for seven consecutive years now and have never seen any mold or smells at all. Unit does not run much because nobody is showering, cooking or breathing moisture into the air. You only have to deal with whatever humidity leaks into the house from outside. Electric bill runs about $18 mo. in the Summer using this system.

For what its worth this what I have learned from research and living down here for seven years. I hope it helps