Install a programmable thermostat to automatically adjust your home's temperature when you're away or sleeping. By properly programming such a thermostat, you should be able to reduce heating and cooling costs by 10-15 percent.

Locate the heating thermostat on an inside wall and away from windows and doors. Cold drafts will cause the thermostat to keep the system running even when the rest of the house is warm enough. Set the thermostat as low as comfort permits. Each degree over 68°F can add 2-3 percent to the amount of energy needed for heating.

Air conditioner
Set your thermostat to 78°F, or as high as comfort permits. When the weather is mild, turn off the AC and open the windows.