Try some (or all!) of the tips before to get a fast return on your effort of making your home more energy efficient. Spray foam or caulk air leaks Weatherstrip doors Install LED bulbs, saving approximately 80% of cost of lighting house Use a smart thermometer to adjust temperatures Lower furnace thermostat 5 degrees at night or when away from home to save 15% on energy bill Raise AC thermostats or use fans to reduce energy costs Set water heater temperature to 120° Close blinds/curtains at night Cover doorway with draft excluder Check out Energy Saver tips at energy.gov/energysaver