[Dr Winston O Boogie jr]

Originally Posted by SIRE1

I also thought I should have a humidistat for the summers when we go back to Michigan and had one installed. When I tried to use it, however, I found that the AC would only run if the humidity got above the set level. But the AC would NOT run if the temperature in the house got over the thermostat setting. I had thought the AC would run if either the thermostat OR humidistat settings reach, but I found out it wasn't.

So now, I just leave the humidistat to ON (i.e. not engaged), and rely on the thermostat to trigger the AC when the temp in the house is over 80 degrees. I'm sure some of the newer humidistat will turn on the AC if either condition is met, but just to let you know what to look for if you decide to have one installed.

That is actually the whole idea behind having a humidistat. If you set the AC to come on at 80 when you are away in the summer, it will run all day and much of the night. Since the humidity and not the heat is what is harmful to the inside of your home, a humidistat will only allow the AC to come on when the humidity rises above the pre set level regardless of temperature. It is not intended as a dehumidifier when you you are occupying the home. I had one back in the 80s when I was a Sarasota snowbird.