Here are some tips from energy.gov to help you manage your thermostat.
Each degree you raise your thermostat can help you save up to 5% in cooling costs.
You can save as much as 10% a year on heating and cooling by turning your thermostat 7 degrees to 10 degrees higher than you normally would in warm months and 7 degrees to 10 degrees lower in cold months for 8 hours a day. The percentage of savings is greater for buildings in milder climates than for those in severe climates.
In the summer, keep your house warmer when you are away.
Raise the temperature when you are at home. Set your thermostat as high as comfortable and ensure humidity control if needed. Consider setting the thermostat at 80 degrees while you are away.
The smaller the difference between the inside and outside temperatures, the lower your energy bill will likely be.
Avoid setting your thermostat at a colder setting than normal when you turn on your air conditioner. It will not cool your home any faster and could result in excessive cooling and expense. A higher interior temperature will slow the flow of heat into your house and save energy on air conditioning.
For more tips and energy-saving ideas: duke-energy.com/summer