Everyone’s idea of “cold enough” is a little different but setting your home’s interior temperature to “meat locker” all day will lead to high energy costs. Instead, set the daytime temperature as warm as you can stand it and challenge yourself to a temperature slightly higher than you think you’ll like.
If you come and go on regular schedule most days, a programable thermostat can be a powerful tool to combat energy costs. Setting the temperature to the coolest just before you regularly go to bed will cool your home when energy demand is at its lowest and will most efficiently cool you down when the sun is not baking your roof. Setting it a little higher just before you wake up might make it a little easier to crawl out of bed in the morning and setting it for a temperature just above what you find comfortable for the hours you are typically away from the house will save even more.
If you’re going to be away from home for a while, do not turn the AC off completely. Instead, turn it up as high as you dare, minding your pets’ needs if they’re at home. It is unwise to turn your AC off completely when you’re away from home, as the energy used to cool an extremely hot space back down to a comfortable range is greater than the energy used to maintain a moderately cool space. Air conditioning also manages indoor humidity, so a home left with the AC off for an extended time can become hot and humid quickly.