Lexington Global Warming Action Coalition
Carbon Footprint Calculator


This calculator calculates only the Carbon Footprint (carbon dioxide emissions) generated directly at the household level. Other less direct but significant contributers related to consumption patterns and other lifestyle areas are not addressed.

Requirements and Instructions:

This calculator was designed to require minimal input. These few inputs do require some advance preparation on your part. The required inputs to successfully complete the calculator are:

1. Basic knowledge of types of energy used in household: electric, natural gas, heating oil, and renewables.
2. Total kilowatt hours of electrical use for last 12 months - see most recent NSTAR electric utility bill.
3. If applicable, total therms of natural gas usage for last 12 months - see most recent Keyspan utility bill.
4. If applicable, total gallons of heating oil used in last 12 months.
5. The number of automobiles or other means of personal transportation in household.
6. The EPA "combined" miles per gallon rating of each vehicle. (EPA "combined" mileage ratings can be found at http://www.fueleconomy.gov/feg/sbs.htm)
7. An estimate of the miles driven by each vehicle for the last 12 months.

NOTE: Only the red shaded fields require numerical inputs. All fields displaying numerical information with white background are calculation results.

IMPORTANT: Your browser must have JavaScript enabled to use this calculator.

Home Energy Use
Background Information on Household

Some basic information on your household is required to generate some average energy use/carbon footprint values and to estimate a distribution of your household's energy use.

Fuel used for various household tasks:

Air Conditioning:

Current Home Energy Carbon Foot Print

The amount of carbon-based energy coming into a house over the past year is relatively easy to establish through a review of billing histories (The preceding 12 months of electrical and natural gas use are listed on each monthly bill). This is the most precise step of the footprint calculation and forms the baseline from which any conservation actions and efficiency improvements are measured1.


lbs of CO2

% CO2

lbs of CO2

Home Energy Audit

Using your basic household information and a few rules of thumb, this simple home energy audit distributes the above calculated carbon emissions across various energy consuming tasks in the household. The intent is to make you aware of the origins your household's carbon emissions. A comparison is made to an average New England household2.

Home Heating
 pounds of CO2
 pounds of CO2

Recommendations and comments:

1. Reducing your heating thermostat will nominally reduce these emissions by 4% for each of the first few degrees of reduction.

2. Setting back your thermostat for 8 hours at night will nominally reduce emissions by 1% for each degree of setback. Setting back at other times also helps.

Domestic Hot Water
 pounds of CO2
 pounds of CO2

Recommendations and comments:

1. Confirm that your water heater thermostat set no higher than 120 degrees (most new water heaters are preset at 120 degrees). If it is set higher, a 10 degree reduction can reduce your carbon emissions due to water heating by 5%.

Air Conditioning
 pounds of CO2
 pounds of CO2

Recommendations and comments:

1. Equip your central air conditioner with a programmable thermostat.

2. Put your window air conditioner on a timer.

General Electrical Use
 pounds of CO2
 pounds of CO2

Recommendations and comments:

1. A single 60 watt light bulb used 4 hours per day generates 93 lbs of CO2 annually. Turning off unnecessary lighting is an easy way to decrease your carbon emissions.

2. A Compact Flourescent Lightbulb (CFL) in place of one of these 60 watt light bulbs would generate 28 lbs of CO2 (65 fewer pounds per bulb). Use CFLs in your high use lighting fixtures.

3. An average television or computer running for 8 hours per day generates 618 lbs of CO2 annually. A laptop computer would generate 77 lbs of CO2 annually.

Personal Transportation Energy Use
Current Automobile Carbon Foot Print


lbs of


Miles per

lbs of CO2

Recommendations and comments:

1. If you have several vehicles, consider using the higher mileage vehicle whenever possible.

2. Several gas mileage tips can be found at http://www.fueleconomy.gov/feg/drive.shtml

Personal Airline Travel

Personal airline travel is a large source of CO2 emissions. This calculation is beyond the scope of this calculator, but an easy-to-use carbon footprint calculator for airline travel can be found at http://www.terrapass.com/flight/flightcalc.html. Several per-person carbon footprints for various round trip flights from Boston are listed below.

Orlando, Florida: 1009 pounds

Los Angeles, California: 2030 pounds

London: 2546 pounds

Tokyo: 5228 pounds

Melbourne, Australia: 8205 pounds

Sao Paulo, Brazil: 3747 pounds

To include CO2 emissions for your household's personal airline travel in this calculation, go to the calculator at terrapass.com and enter the result below.

lbs of CO2

Your Household's Carbon Footprint Summary

The preceding home energy and personal automobile transportation carbon footprints are repeated here and combined for the total carbon footprint directly attributed to your household.

lbs of CO2

% CO2


lbs of CO2

tons of CO2

Use your browser's print button to print this calculator .

1Carbon conversion factors are taken from: http://www.eia.doe.gov/cneaf/electricity/page/co2_report/co2emiss.pdf
2Average New England energy use can be found in Residential Energy Consumptions Surveys for 2001 at http://www.eia.doe.gov/emeu/consumption. Note that the average New England household as used here does not account for the number of members in household, nor does it take into account the physical household, condo, or apartment size.
3The average New England space heat calculation uses the same fuel as your household. If your household uses a renewable source then oil is used for the average calculation.
4Footnote #3 applies to domestic hot water also.
5The average New England calculation is based simply on the use of air conditioning in household. No distinction is made between whole house or window types.

Contacting us

If you would like to contact us, please email us at info@LexGWAC.org.