Hello. We purchased a house with geothermal already installed and I have a couple of questions. First let me tell you our set up. We have two units, downstairs (5 ton)/upstairs (4 ton). The downstairs has a dehumidifier hooked up to it. I had been turning it way up during the day (78°) and down at night (74°). I just learned that you shouldn't do that with geothermal so now I'm trying to "set it, forget it". Tough to break old habits. So my questions are: We live on the east coast. If I keep it at 74° the whole day it gets freezing in here but keeps the humidity levels upstairs manageable. The downstairs has very dry air but the upstairs does not. Is 74° to cold to keep it when the temps are 95° outside energy cost wise? The hvac guy told me with geothermal it didn't matter cost wise if you had it on 85° or 60°. To run it what you wanted. Is this true? Thank you for your time!