Rex says
Everyday utility math — the kind you'd otherwise pull up four browser tabs for. I keep it to one clean answer.
Try a scenario
Click to load — tweak from there.Inputs
Result
Total annual home CO2 (kg)
6,535
Total (metric tonnes)
6.54
From electricity
3,885
From natural gas
2,650
From heating oil
0
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How to use this
- 1Enter annual electricity use (kWh).
- 2Enter grid carbon intensity (kg CO2/kWh).
- 3Enter annual natural gas use (therms).
- 4Enter annual heating oil use (gal).
- 5Read your total annual home co2 (kg) on the right — it updates as you type.
- 6Hit Share to keep the scenario or send it to someone.
About this calculator
Home energy use typically makes up 15-25% of a US household's total carbon footprint, split between electricity (whose carbon intensity depends entirely on your local grid mix) and direct fuel combustion for heating and hot water, which emits a fixed amount of CO2 per unit regardless of where you live. This calculator combines your annual electricity usage times your grid's carbon intensity with your natural gas or heating oil usage times EPA emission factors, giving a household total in line with how EPA and utility carbon-tracking tools calculate it. Natural gas emits about 5.3 kg CO2 per therm and heating oil about 10.16 kg CO2 per gallon — both fixed regardless of furnace efficiency, so efficiency only changes how many units you burn, not the per-unit factor.
Worked example
Using the values the calculator loads with:
Inputs
- Annual electricity use: 10500 kWh
- Grid carbon intensity: 0.37 kg CO2/kWh
- Annual natural gas use: 500 therms
- Annual heating oil use: 0 gal
Results
- Total annual home CO2 (kg): 6,535
- Total (metric tonnes): 6.54
- From electricity: 3,885
- From natural gas: 2,650
- From heating oil: 0
What each field means
Inputs
- Annual electricity use (kWh)
- The annual electricity use used in the calculation, measured in kWh. Starts at 10500 kWh so you have a working example on load.
- Grid carbon intensity (kg CO2/kWh)
- The grid carbon intensity used in the calculation, measured in kg CO2/kWh. Starts at 0.37 kg CO2/kWh so you have a working example on load. Accepted range: 0–1 kg CO2/kWh.
- Annual natural gas use (therms)
- The annual natural gas use used in the calculation, measured in therms. Starts at 500 therms so you have a working example on load.
- Annual heating oil use (gal)
- The annual heating oil use used in the calculation, measured in gal. Starts at 0 gal so you have a working example on load.
Results
- Total annual home CO2 (kg)
- Returned as a whole number and shown as the headline result. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Total (metric tonnes)
- Returned as a decimal number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- From electricity
- Returned as a whole number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- From natural gas
- Returned as a whole number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- From heating oil
- Returned as a whole number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
FAQ
Why does the same electricity usage produce different emissions in different homes?
Grid carbon intensity varies by region based on the generation mix — coal-heavy grids emit far more CO2 per kWh than grids dominated by hydro, nuclear, wind, or solar. The same 10,000 kWh of annual use can range from under 1,000 kg CO2 to over 7,000 kg depending purely on location.
How can I lower my home's carbon footprint fastest?
Switching from resistance or oil heat to a heat pump usually delivers the largest single reduction since it moves heating from direct fuel combustion to electricity, which you can then decarbonize further with rooftop solar or a green power plan from your utility.
Why don't furnace or water heater efficiency ratings appear in this formula?
Efficiency changes how much fuel you burn for a given heat output, which is already reflected in your actual therms or gallons used on your utility bill — the emission factor per unit of fuel burned stays fixed regardless of appliance efficiency.
Is natural gas cleaner than heating oil for the same heat output?
Per unit of heat delivered, natural gas generally emits less CO2 than heating oil, and modern high-efficiency gas furnaces (95%+ AFUE) further reduce fuel burned per BTU delivered compared to older oil systems, though methane leakage upstream in the gas supply chain is a separate, harder-to-quantify factor.
Accuracy and limitations
- Estimates assume standard, average conditions — local rules, pricing, and materials vary.
- Results are rounded for readability; add a buffer before ordering, booking, or committing.
- Double-check anything with a real cost attached against a local quote.
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Tree Carbon Offset Calculator
Estimate how many trees and years are needed to offset a given amount of CO2.
Cite this calculator
Writing about this topic? Grab a citation — every link helps keep these tools free.
RevenueLab. (2026). Home Carbon Footprint Calculator. Retrieved from https://www.revenuelab.fyi/toolbox/carbon-footprint-home
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/carbon-footprint-home" target="_blank" rel="noopener">Home Carbon Footprint Calculator — RevenueLab</a> (2026).</p>
Source: [Home Carbon Footprint Calculator — RevenueLab](https://www.revenuelab.fyi/toolbox/carbon-footprint-home) (2026).