Home Energy Emissions Calculator Formula

Understand the math behind the home energy emissions calculator. Each variable explained with a worked example.

Use the Home Energy Emissions Calculator

Formulas Used

Total Annual CO2

total_tons = (elec_lbs + gas_lbs + oil_lbs + propane_lbs) / 2204.6

Electricity CO2

elec_tons = elec_lbs / 2204.6

Natural Gas CO2

gas_tons = gas_lbs / 2204.6

Oil & Propane CO2

fuel_tons = (oil_lbs + propane_lbs) / 2204.6

Variables

VariableDescriptionDefault
elec_kwhMonthly Electricity(kWh)900
gas_thermsMonthly Natural Gas(therms)40
oil_gallonsAnnual Heating Oil(gallons)0
propane_gallonsAnnual Propane(gallons)0
elec_lbsDerived value= elec_kwh * 12 * 0.92calculated
gas_lbsDerived value= gas_therms * 12 * 11.7calculated
oil_lbsDerived value= oil_gallons * 22.4calculated
propane_lbsDerived value= propane_gallons * 12.7calculated

How It Works

How to Calculate Home Energy Emissions

Home energy emissions come from the fuels used to power and heat your home.

Emission Factors

  • Electricity: 0.92 lbs CO2/kWh (US grid average)
  • Natural Gas: 11.7 lbs CO2/therm
  • Heating Oil: 22.4 lbs CO2/gallon
  • Propane: 12.7 lbs CO2/gallon

    • Formula

    Total CO2 = Sum of (Usage * Emission Factor) for each fuel / 2,204.6

    Worked Example

    A home using 900 kWh/month electricity, 40 therms/month gas, no oil or propane.

    elec_kwh = 900gas_therms = 40oil_gallons = 0propane_gallons = 0
    1. 01Electricity: 900 * 12 * 0.92 = 9,936 lbs CO2
    2. 02Natural Gas: 40 * 12 * 11.7 = 5,616 lbs CO2
    3. 03Total: 15,552 lbs / 2,204.6 = 7.06 metric tons/year

    Ready to run the numbers?

    Open Home Energy Emissions Calculator