There was a post re: above this morning, which I replied to. The site was having problems. I did see my response to the original post, but it seems to have disappeared.

Here is a copy of my reply:

What type of auxiliary heat do you have? Electric strip heat?

If so, could be set up so that aux heat is coming on too soon, and may worsened by a large setback at night (or away), as the unit may jump directly to aux heat. Also, since your house is large, the size of heat strips could be large, and if not staged, you get all or nothing. They can be energy hogs.

What is your location (city & state), and model numbers of outside and inside unit (air handler, assuming you have strip heat), and size of strips if known.

V