This simple calculator assumes that incandescent bulbs are the most common 60-watt bulbs, and that CFLs provide 75 percent savings and LEDs provide 80 percent savings, based on the performance of the models on the market in 2011. Relying on the latest U.S. government and state of California studies, it assumes the typical household lamp is used 1.9 hours per day. The calculator uses the U.S. government's estimate that the average household has 40 light bulbs. Based on the U.S. market profile for 2010, the calculator assumes 16 percent of light bulbs, or an average 6.4 per household, are CFLs.

Calculations are based on 2010 U.S. Census data showing 113.7 million households in the United States.

Figures on carbon emissions are based on the U.S. Environmental Protection Agency's assumption of 1.37 pounds of carbon dioxide equivalent (CO2e) for every household kilowatt-hour of energy consumed. The calculator also uses EPA's green power equivalency assumptions, of 5.1 metric tons of CO2e for every car, 183.65 metric tons CO2e for every coal railcar, and 4,023,304 metric tons CO2e annually for every power plant.

Cost calculations are based on the average residential price of electricity in the United States in 2011, 11.6 cents per kilowatt-hour.

Credits: Programming by Stefan Estrada. Illustrations by H2H Graphics & Design. Text by Marianne Lavelle. Production by Christina Nunez.

Share

Personal Energy Meter

See how you measure up against others, and how choices you make at home and in the way you travel could help to protect the atmosphere.

Select a country below to get started:

Continue »
%%CLICK_URL_UNESC%%

Did You Know?

Fourteen nations and Europe account for about 80 percent of world greenhouse gas emissions. See four ways to look at global carbon footprints.

More About Energy

  1. Photo: Aerial view of a city at night

    The Great Energy Challenge

    The National Geographic initiative is a call to action to become actively involved, to learn more and do more—to change how we think about and consume energy so that we can all help tackle the big energy questions.

  2. An interactive map shows four ways to look at carbon emissions around the world.

    Global Greenhouse Gas Footprints

    See how the world's biggest economies stack up on emissions with an interactive map.

  3. The changing Arctic: interactive map from National Geographic

    Interactive Map: The Changing Arctic

    See the shrinking sea ice, increased shipping, and energy exploration sites that are part of an evolving picture of the Arctic.

  4. Screenshot from an interactive bubble map of fossil-fuel subsidies worldwide

    Global Fossil-Fuel Subsidies Map

    See which countries pay the most for tax breaks and other mechanisms that keep fossil-fuel prices down.

  5. An incandescent light bulb.

    Light Bulb Savings Calculator

    How much could you save yourself, and the world, by switching to more efficient bulbs? Use this tool to find out.

  6. World Electricity Mix interactive map

    The Global Electricity Mix

    An interactive view of how regions and countries around the world generate their power.

  7. A sugar palm energy researcher.

    Great Energy Challenge Grantees

    Learn more about the energy-saving projects being funded as part of National Geographic's Great Energy Challenge program.

Future of Energy

  1. Hydrogen storage research at Brookhaven National Lab

    What Energy Solution to Develop Next?

    Renewables, natural gas, a yet-to-be discovered breakthrough... what should we be focusing on now?

  2. _DSC0719.jpg

    Experts Eye the Future for Brazil’s Energy Mix

    Experts gathered in Sao Paulo to discuss the roles of biomass, hydropower, and other key issues.

See more »

@NatGeoGreen on Twitter

The Big Energy Question

What innovation should shape transportation in the future?

Vote and Comment »

Special Report: Shale Gas Rush

  1. The Hallowich family  Stephanie, Chris,  Children--Alie and Nate

    A Dream Dashed by the Rush on Gas

    The shale gas industry maintains that it protects drinking water and land. But mistrust has been sown in rural communities.

  2. Lee Zavislak learns to drive an 18-wheel truck at the Western Area Career and Technology Center in Canonsburg, Pennsylvania.

    New Jobs Through Energy

    The industry promises jobs to a state badly in need of an economic boost, but the work so far isn't where you might expect it to be.

  3. shale-map_503x465.jpg

    Mapping a Gas Boom

    Track the growing mark that energy companies have etched on Pennsylvania since first producing natural gas from shale.

View Our Complete Shale Gas Coverage »