Are you asking about heating the home when the outside air is below 60 degrees? That is unlikely for us unless there are multiple days around 60 degrees.

For context, I live in the middle of America. We can get -10 to -20 degrees in the winter and 100+ degrees in the summer. When it is winter, we will have the inside temperature around 68 degrees. In the summer, we set the inside temperature at 75-78 degrees is about normal for us.

Right now we are having cool nights and warm days so we open windows at night and close them during the days. I think our house was in the low 60s (inside) this morning. The second story will likely get warm by this evening so the air may kick on upstairs.