Action: Wash Laundry on a Cooler Setting

Why It’s Worth It: About 90 percent of the energy used to wash clothes goes to heating the water. Assuming you already wash half your laundry in cold, moving the other half from hot to warm can save a substantial amount of energy.
Your One-Year Effect: 349 pounds of CO2 saved.
The Effect If Everyone in the U.S. Did It For One Year: Equal to 3,316,442 cars taken off the road for one year.

Action: Switch Five Lightbulbs to Compact Fluorescent Lightbulbs

Why It’s Worth It: A 25-watt compact fluorescent lightbulb (CFL) provides the same amount of light as a 75-watt incandescent. CFLs use a third of the energy and last 10 times longer. Switching five bulbs could save about $400 over the CFLs’ lifetime.
Your One-Year Effect: 500 pounds of CO2 saved.
The Effect If Everyone in the U.S. Did It For One Year: Equal to 4,751,350 cars taken off the road for a year.

Action: Compost a Fifth of Your Garbage

Why It’s Worth It: Putting less trash on the curb reduces the amount of fuel required to haul it away. Plus, composting food scraps, like apple cores, keeps them out of landfills, where they can break down to release a potent greenhouse gas.
Your One-Year Effect: 832 pounds of CO2 saved.
The Effect If Everyone in the U.S. Did It For One Year: Equal to 7,906,246 cars taken off the road for one year.

Action: Modify the Temperature on Your Thermostat

Why It’s Worth It: There’s no reason to keep the house perfectly heated or cooled when you’re not there to appreciate it. Modifying the temperature just four degrees with a programmable thermostat will save energy — and about $130 a year.
Your One-Year Effect: 1,300 pounds of CO2 saved.
The Effect If Everyone in the U.S. Did It For One Year: Equal to 12,353,510 cars taken off the road for one year.