If we get to low single digits, the third stage (heat strips) kick in for about an hour. The difference is with the new thermostat, we KNOW is it on...previously we never could tell without going downstairs.
That is amazing, that you haven't hit third stage; when we thought that, we ended up with quite an eletric bill when we first installed the geo (and after some fine-tuning the problem went away).
It probably has something to do with the sizing of your system. How many tons have you?
