It is easy to reach 46'F. I'm in MA, this week is very cold, and if I turn off the furnace in the attic during the night, the second floor is about that temperature in the morning. So everyday I will turn on that furnace in the morning and turn off it before I go to work, and again turn on it after I return home and turn off before I go to bed. I found out if I don't heat the second floor, if will be very hard to reach the desired temperature for the first floor.