Replacing five incandescent lightbulbs with compact fluorescents can cut 275 pounds of CO2 emissions per year. Taking the train instead of flights under 500 miles can bypass 310 pounds of CO2. Shortening showers from eight to five minutes saves 513 pounds of CO2 annually, and weatherizing homes through caulking and insulation prevents hundreds of additional pounds of CO2 depending on the type of heating. Using fans instead of air conditioning as much as possible and replacing old refrigerators with Energy Star models also significantly reduces household CO2 emissions.