I live in a well insulated apartment and the sun doesn't shine directly on my unit because of the design and the positioning of my building. My air condition cool my place very quickly & I can leave the temperature on around 70 degrees and it stays perfect. However, I live alone, so when I'm not home, I usually turn my air off to save money. I know it can cost more to turn on and off because that makes the air stay on longer to chill a hot house, but I don't have that problem. Even on the hottest days, my place remains cool for the most part. Do you leave your air on when away?