Check out our new home energy emissions calculator and win fabulous prizes

Our new home energy emissions calculator uses a combination of energy prices, regional energy usage patterns and local emissions data to calculate your home energy emissions. If it sounds complicated, that’s because it is. The same $100 spent in one part of the country might have a completely different emisions profile than $100 spent in another.

For those intrigued by these variations (or perhaps just seeking a few minutes of distraction), here’s our challenge: with a budget of $100, what combination of expenditure on home energy produces a) the highest carbon emissions and b) the lowest carbon emissions?

Post entries in the comments to this blog post. A valid entry will consist of a ZIP code, a set of energy bills totaling up to $100, and a total pounds of CO2.

Note that there are several factors at play here. In regions with low energy prices, $100 will buy more energy (and therefore more carbon emissions). In regions with particularly dirty energy, $100 will also buy more carbon emissions. And vice versa. So the winning entries will be ones which find the magic combos of cheap and dirty energy vs. expensive and clean.

We’re giving away $100 in gift certificates – $50 to the highest emissions and $50 to the lowest. When you post your answer below, remember to include your email address so we can get in touch with you. Don’t worry, it won’t be displayed publicly.

The competition will officially close one week from today, although the winners will probably submit their entries long before then. You have to use $100 and should only use it on gas and/or electricity. And don’t bother messing with the finetuning controls on the calculator results. We’ll know!

Have fun!

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  1. Paul - September 6, 2006

    78736: Emissions = 0

    We buy 100% of our electricity from Austin Energy’s GreenChoice program — 100% wind power:

    We don’t have a gas hook-up at our house.

    I guess this means we are not qualified to compete, since we’ve already reduced our house emissions to zero.

  2. William - September 6, 2006

    Last year I used to offset my emissions, because I could offset flight, electicity and natural gas emissions with them. Now that TerraPass has these in their protfolio and TerraPass has always been better about ensuring these are real reductions, I will probably use TerraPass for my 2006 emissions.

  3. Steve - September 6, 2006

    Spend $100 on electicity in Vermont and create 44 Lbs of Co2 emissions. (probably due to clean imports of hydro power from Quebec :-))
    Zip Code:05672
    State: Vermont
    Mix: 100% Electric
    * Co2 Emission Factor: .06 Lbs per Kwh
    ** $\kwh:.1294
    # Kwh purchased with $100:772
    Lbs Co2 emissions:44
    Idaho & Washington were not far behind.
    Oddly enough ..the Terrapass Calculator is using a Co2 factor of 0.90 lbs per kWh! I couldn’t find any tables with that factor. I suspect that Vermont comes up on top regardless of which tables are used.
    Spend $100 on electricity in Kentucky and create 3649 lbs of Co2 Emissions! (Probably all coal,no nuclear)
    Zip Code:42021
    State: KY
    Mix: 100% Electric
    * Co2 Emission Factor: 2.23 Lbs per Kwh
    ** $/kwh:.0611
    # Kwh with $100:1637
    Lbs Co2:3649
    Note: North Dakota,West Virginia ..not far behind.
    * Co2 Emission Factors were retrieved from
    Table 3. State-Level Average All (Total) Generation Electricity Emission Factors
    ** Average Price per kwh was retrieved from
    For those interested in Canadian Stats ..
    British Colombia,Manitoba and Quebec are very low emitters (Mostly Hydro) whereas Alberta and Saskatchewan are highest emmitters (Mostly Coal)

  4. Johnny - September 6, 2006

    Emissions from your home energy use
    Your home’s emissions are
    below average for California
    2,971 pounds of carbon dioxide per year
    This is equivalent to burning 152 gallons of gasoline!

  5. Michael Brown - September 6, 2006

    I live in a large 19th century mansion with 6 housemates. As you can imagine, despite usings only CFL bulbs and trying to conserve energy, we produce 89,617lbs of CO2 per year according to the calculator on this site!!
    I have a Terrapass for my car and we are going to switch to a renewable provider for electric; however, displacing the CO2 from the 1600 gallons a year of heating oil we use is quite a hefty endeavor!

  6. JuliaZ - September 6, 2006

    ZIP Code: 98072
    State: Washington
    100% electricity, and we pay extra to get 10% from renewable sources (much of our power is hydro anyway)

    Our emissions are below average for the state of Washington.
    We produce 4248 pounds of carbon per year (4 people, 4Br, 2.5Ba)
    217 gallons of gas equivalent
    We get 1400 kwH for $100 if we pay extra to use renewable sources.

    My old house in Newcastle (20 miles away) was a comparative nightmare, though the calculator says it was about average for the state.
    ZIP Code: 98056
    Energy source: electricity and heating oil
    We produced 19,292 pounds of carbon per year (2 people, 4Br, 1 Ba)
    986 gallons of gas equivalent

    I loved that old house but it was poorly insulated and I suppose I’m glad to be out of it, when viewed through this lens!

  7. Ric - September 6, 2006

    The lowest I get at 98103 (Seattle) is by using $100 on propane:

    641 pounds CO2


    heating oil: 906 pounds CO2
    electric: 10,360 pounds CO2
    gas: 46,029 pounds CO2

    Poster #2, how did you come up with 44 pounds CO2? I plugged in your zip code and got 6614 pounds CO2.

  8. pete - September 6, 2006

    I think poster #2 has used state by state emissions data, which does give an extremely low emissions rate for Vermont.

    We looked at the state emissions data during the devlopment of the produict, but opted to go for official numbers provided by the EPA. These take account of energy trading between states and are thought to be more reliable.

    You can check your own ZIP’s emissions either by clicking on the “finetune” link on our calculator or by playing with the EPA’s own Power Profiler.

    A couple of more general points on the competition: you must spend your $100 on electricty and/or gas (no propane), and use the TerraPass calculator’s emissions rates. And for the purposes of theis exercise, no allowances for green electricity!

    Thank you for all of your comments. Keep ’em coming! Pete.

  9. Steve - September 6, 2006

    Heh Ric ..

    I probably misunderstood the challenge. I assumed that we only had $100 to spend on energy (not $100 per month) and had to find out what places in the U.S. would give you more “bang for the buck” in terms of Co2 emmissions. I don’t think emmissions from Natrual Gas, Propane or Oil differ by state .. but I do know that emmissions from electricity generation varies greatly from one state (or region) to another.

    I actually downloaded data (CO2 Emmission Factors for Electricity Generation + cents per kilowatt by state) into a spreadsheet to try and find the “magic combos”. Regardless of how many kwh’s are purchased ($100 or $1200 worth), the really important number is the emission factor used to calculate lbs of CO2 for a given state. When going through the terrapass calculator there is a link called “fine tune this calculation” on the initial result screen. This link displays (in the right hand side) some of the assumptions used by terrapass for the calculations. Here’s what shows up for zip codes in Vermont.

    CO2 emissions data for Stowe, VT
    Electricity: 0.90 lbs per kWh
    Natural gas: 120.59 lbs per Mcf
    Heating oil: 22.38 lbs per gallon
    Propane: 12.67 lbs per gallon

    When I looked at U.S. government data (see URL in initial posting) the Vermont emmission factor for Electricity is stated to be .06 lbs per kwh rather than .90 used by terrapass (thats a big difference!).

    BTW: The Kentucky numbers matched what I had found on the internet.

    In the end , I used $100 and a factor of .06 lbs. rather than $1200 and .90. Hence the big difference. In the end I’m unsure which state has the least emmissions. I suspect that the fine folks at terrapass have harvested more accurate information than I could muster up in a few minutes searching on the internet.

    Note:I used a zip code in Stowe because I have a friend who lives there .. I’m actually in Ontario Canada! Our electricity emmission factor is ~0.25 kg per kwh (~ .6 lbs) due to a mix of hydro,nuclear,coal and renewables.

    Cheers and good luck to everyone.

  10. Steve - September 6, 2006

    Zip Code:98012
    State: Washington
    Mix: 100% Electric (mainly hydro)
    Average kWH/month: 521.25
    Cost/kWH: 7.9c
    CO2 emissions/year: 4191 lbs
    So per $100, I’d emit 848 lbs of CO2.

  11. Londa - September 6, 2006

    Entering $100 all-electric into the calculater, for Niagra Falls NY, ZIP code 14303, I get a pretty low amount: 4,902 pounds of carbon dioxide per year. I betcha they might use some hydroelectric power up there.
    On the other hand, entering $100 all-electric into the calculator, for Morgantown WV, ZIP code 26501, I get a very high amount: 30,997 pounds of carbon dioxide per year. I am guessing they might be using some of that nice soft, abundant, cheap coal…
    Great contest! BTW, Americans use around 1/2 of Europeans for home energy use. Personally, I am not quite down to that yet, but working on it:)

  12. Londa - September 6, 2006

    OOPS, correction. I meant to type that Americans use about TWICE what Europeans do. Sorry for any confusion!