If everyone in the U.S. changed their five most-used light bulbs to CFLs, total U.S. carbon emissions would be reduced by 0.3 percent.

We would save 9 billion pounds of pollution a year if every American home replaced a single light bulb with a compact flourescent blulb (CFL). Replacing five used bulbs would save 45 billion pounds. If you haven’t already made the switch, now’s a good time. Light quality from most CFLs is better than it used to be. 

Compact Flourescent Bulbs. Alex Wong/Getty Images