House Logic recently shared this information
1. Caulk and seal air leaks. Buy a few cans of Great Stuff and knock yourself out over a weekend to seal around:
Savings: Up to $227 a year — even more if you add or upgrade your insulation.
2. Hire a pro to seal ductwork and give your HVAC a tune-up. Leaky ducts are a common energy-waster.
Savings: Up to $412 a year.
3. Program your thermostat. Shelton says 40% of consumers in her survey admit they don’t program their thermostat for energy savings. She thinks it’s even higher.
Savings: Up to $180 a year.
4. Replace all your light bulbs with LEDs. They’re coming down in price, making them even more cost effective.
Savings: $75 a year or more by replacing your five most frequently used bulbs with Energy Star-rated models.
5. Reduce the temperature on your water heater. Set your tank heater to 120 degrees — not the 140 degrees most are set to out of the box. Also wrap an older water heater and the hot water pipes in insulating material to save on heat loss.
Savings: $12 to $30 a year for each 10-degree reduction in temp.
NOTE: Resist the urge to total these five numbers for annual savings. The estimated savings for each product or activity can’t be summed because of “interactive effects. If you first replace your central AC with a more efficient one, saving, say, 15% on energy consumption, and then seal ducts, you wouldn’t save as much total energy on duct sealing as you would have if you had first sealed them. There’s just less energy to save at that point.