Owning a home (or at least this one) is the weirdest heating/ cooling nightmare. Outside temperatures in the 40-60s overnight your not loosing any interior heat, hell you look at the kitchen stove the wrong way the house temp will go up.
The minute the thermometer outside dips below 40 the house starts cooling (Abit rapidly).

Office was a high of 75 and is now 66
Main area of the house had a high of 74 and is now reporting 68