Maintenance is first on the list. Spend the $100 or so it takes to get a contractor out to inspect your heating system. A worn-out filter or unsealed duct could make it 20% less efficient. On your own, clean the filters every month to keep things running smoothly.
Program the thermostat. Set the temperature at least eight degrees lower when you're away from home or asleep. Depending on where you live and the fuel you use, savings could top $300 this winter.
Seal up the house. That winter chill can sneak in and hot air can escape through cracks along window and door frames. Invest in some caulk and weather-stripping to plug up these drafts. A home that's properly insulated and sealed improves efficiency by up to 20% year-round.
Wrap the water heater. A $20 insulation jacket for your water heart makes sure the system isn't working round the clock to give you hot water for your shower. A jacket cuts heat loss by half, and saves you up to 10% of its cost to operate.
Get free heat. Keep shades open during the day to let in the sun, and close them at night to limit heat loss. Switching your ceiling fan to run in reverse - that's clockwise - can also push warm air downward from the ceiling.