How the calculator works
This tool gives a quick, educational estimate of your household’s annual greenhouse-gas footprint in metric tonnes of carbon-dioxide equivalent (t CO₂e). It focuses on the five categories most households can influence directly: home energy, driving, flights, food and waste. Your answers are saved only in your own browser so you can come back and compare.
Methodology and assumptions
| Category | What we multiply | Factor used (rounded) |
|---|---|---|
| Electricity | kWh per month × 12 × (1 − renewable share) | ≈ 0.60 kg CO₂e per kWh (approximate Wisconsin grid average) |
| Natural gas | therms per month × 12 | 5.3 kg CO₂ per therm (U.S. EPA) |
| Propane / heating oil | gallons per year | ≈ 5.7 kg CO₂ per gallon (propane, U.S. EPA) |
| Driving | miles per week × 52 ÷ mpg | 8.89 kg CO₂ per gallon of gasoline (U.S. EPA) |
| Flights | round trips per traveler × household size | ≈ 0.25 t domestic, ≈ 1.6 t international (economy, approximate) |
| Food | diet type × household size | 1.5–3.3 t per person per year depending on diet (published lifecycle averages) |
| Waste | household size, minus recycling and composting credits | ≈ 0.35 t per person baseline |
Important: this is an educational estimate, not an audit. Real emissions depend on your utility’s actual generation mix, vehicle type, flight distances and many other factors. For a precise, room-by-room picture of your home, book a Home Energy & Waste Assessment.