Posted By jadinpvd on 05 Feb 2011 02:13 PM

Does is make sense for auxiliary heat to come on when going from just 70 to 71 degrees?

Is aux heat really coming on with just 1 degree difference?  By aux heat, you do mean the electric heat strips and not stage 2, correct?  I would double check the thermostat wiring, wouldn't be the first time I read about someone hooking it up wrong.  Also, I've read many cases where the thermostat itself was bad.

I would start reading the meter everyday around the same time and keeping track of electric used vs heating degree days.    You could also turn off the breakers to the aux heat strip to be sure they don't turn on.  I'm pretty sure with that model of thermostat it will turn red if the aux heat strips turn on, have you seen it turn red?
   

Posted By dgbair on 05 Feb 2011 08:11 PM
Is aux heat really coming on with just 1 degree difference?

It did sometimes with our thermostat (with a manual adjustment) before I adjusted the settings.  If the inside temperature is close to the point at which the system would come on (about 1f < set point) combined with a 1f manual change (about 2f total) combined with the "urgency" that the thermostat may associate with manual changes, aux engagement can be a real possibility (if the thermostat is not set up to avoid this.)