Ok here is the scoop. My wife always lowers the heat every night when we go to sleep and puts the temp up every morning when we are awake. I insist her to leave the temp at one place because we save more oil. My wife says no because the temp is so high. I explained to her its like drving a car in the city and highway. When your in the city you waste more gas because you keep accerating. On the highway you save gas because you are at one constant speed. Who is right???