Heating and cooling are almost always a home's largest source of energy consumption
. So why spend that money when you're out of town? Instead, set your thermostat to maintain a stable temperature, no cooler than 54 degrees, no warmer than 80 degrees.
Note that this tip doesn't suggest turning off the thermostat altogether. You should keep your home's temperature stable while you're away, whether in summer or winter, in order to prevent condensation, frozen pipes or other potentially damaging effects. (The exception is if you'll be gone long enough to winterize your home, a strategy that will be described in a moment.)
If you're interested in trimming your heating and cooling expenses throughout the year, start by reading this Family Handyman
article, Use Less A/C and Cut your Electric Bill.