If you haven't already done so, maybe it's time to consider switching from a manual thermostat to an electronic, programmable model. Electronic thermostats have become very affordable and can repay their cost quickly through energy savings. Every degree of heat you reduce will cut about 3 percent from your heating bill. If you lower the temperature from 68° to 59°F for an eight-hour period every night, for example, you'll save about 9 percent.
The most sophisticated thermostats operate zone systems that split a house into two or more zones, each controlled by separate thermostatic settings. These thermostats open and close dampers that are set in ductwork, sending warmed or cooled air to the areas where it's wanted.
A programmable thermostat can be set to raise the room temperature a half hour before you get up, then lower it when you head off to work. Before you arrive home, it can readjust the temperature to a comfortable level once again. It can be set to any schedule you desire.