About the Calculator
Live Climate uses the latest in data and methods to make calculating your carbon footprint as simple and accurate as possible. The calculator uses data from the US Dept of Energy’s Energy Information Administration and the US Environmental Protection Agency. The latest methods are taken from both these sources, environmental non-profit groups, and universities.
To learn the details of how each carbon calculation is made, click Learn More in each section of the calculator. To get an even better understanding of your carbon footprint, visit the Cool Climate Calculator at the Berkeley Institute for Environment.
Home Calculator Description
The carbon footprint for your home is based on your type of home and the state you live in using a method developed by Earthlab.com.
Electricity:
Your home’s carbon footprint is based on your usage of electricity and natural gas. The primary determinant of your home energy use is the size of your home. To determine your carbon footprint from electricity use, the calculator uses the average electricity consumption in your state as a baseline.(1) The calculator then multiplies this baseline by a scaling factor for your home size and for the number of bedrooms in a home that size. Apartments are scaled to consume 50% of the electricity of an average household, and single family-attached homes (townhouses) are scaled to consume 75% of the electricity of an average household.
Finally, different states have different levels of pollution in their electricity generation.(2) The calculator multiplies your estimated annual electricity use by the average emissions factor of electricity generation in your specific state to give you a reasonable estimate of your home’s carbon footprint from electricity.
[1] US Department of Energy, Energy Information Administration, “Electric Sales, Revenue, and Average Price 2004,” http://www.eia.doe.gov/cneaf/electricity/esr/esr_sum.html Table 5, “U.S. Average Monthly Bill By Sector, Census Division and State,” http://www.eia.doe.gov/cneaf/electricity/esr/table5.xls Each state’s monthly consumption average in the table was multiplied by 12 to calculate yearly average consumption.
[2] Emissions data taken from the United States Environmental Protection Agency’s EGRID Dataset. http://www.epa.gov/cleanenergy/energy-resources/egrid/index.html
Natural Gas:
Since natural gas is primarily used for heating, the size of your home is the primary determinant of how much natural gas is used. To determine your carbon footprint from natural gas use, the calculator starts with average natural gas consumption from your state as a baseline.(1) The calculator then multiplies this baseline by a scaling factor for your home size and for the number of bedrooms typical in a home that size. For example, the baseline natural gas consumption is scaled by 50% for an apartment and then by 80% since an apartment will generally have less than 3 bedrooms.
Finally, the carbon emissions from burning natural gas are multiplied to the estimate for your home’s natural gas use.
[1] Natural Gas Emissions Coefficient from: http://www.eia.doe.gov/oiaf/1605/coefficients.html
Auto
The carbon footprint for each car is calculated based on the number of miles driven and the mileage that your car gets per gallon. By dividing your miles driven by your car’s miles per gallon (MPG), we can determine how many gallons of gas your car used that year. Each gallon of gas burned emits 8.87 kg of carbon dioxide.(1) To calculate your car’s footprint, we multiply this factor with the number of gallons used.
[1] http://www.eia.doe.gov/oiaf/1605/factors.html
Air Travel
Airplanes burn most of their fuel during takeoff and landing. For that reason, the emissions factor for a short flight is higher than longer flights.(1) The average short flight emits 0.25 kg of carbon dioxide equivalent per passenger for every mile flown. The average long or extended flight emits 0.17 kg of carbon dioxide equivalent per passenger for every mile flown.
To make calculating your footprint simple, the Live Climate calculator uses the average length in miles of short, medium, long, and extended flights. We multiply this average length by the number of flights you take in each category to get miles flown in each category. Finally, the calculator uses the emissions factor for each category to calculate your total carbon footprint from air travel.
[1]“Passenger Transport Emission Factors – Methodology Paper”, Department for Environment, Food, and Rural Affairs, United Kingdom, June 2007
[2] http://www.eia.doe.gov/oiaf/1605/coefficients.html