How US carbon emissions are calculated
Emissions are measured in short tons of carbon dioxide equivalent (tons CO2e) under US Environmental Protection Agency (EPA) and eGRID guidelines.
Electric grid power is calculated at approximately 0.85 lbs CO2e/kWh, residential natural gas at 11.7 lbs CO2e/therm, vehicle mileage at 0.89 lbs CO2e/mile, plus baseline consumption.
Worked example
For an average US household consuming 10,500 kWh electricity, 600 therms natural gas, driving 13,500 miles and flying 6 hours per year:
Home energy produces 7.97 tons CO2e, transport produces 6.68 tons CO2e, and baseline goods add 4.50 tons, totaling 19.15 short tons CO2e annually.
Inputs for the US carbon footprint calculator
Annual electricity consumption
Total annual household electricity usage in kWh (US average is ~10,500 kWh/yr).
Annual natural gas consumption
Total annual natural gas usage in therms (US average is ~600 therms/yr).
Annual vehicle mileage
Total miles driven in personal vehicles each year (US average is ~13,500 miles/yr).
Annual commercial flight hours
Total hours spent on commercial passenger flights over the year.
CALCULATOR QUESTIONS
Carbon footprint calculator US questions
What is the average US carbon footprint per capita?
The US national average is approximately 14.5 short tons of CO2 equivalent per person annually, which is higher than most other industrialized nations.
How are therms converted to CO2 in the US?
Under EPA emission factors, burning one therm of domestic natural gas emits approximately 11.7 pounds of carbon dioxide equivalent.