Estimate your CO2 emissions from electricity usage based on your local power grid's carbon intensity.
Your electricity carbon footprint is determined by multiplying the total electricity you consume (in kilowatt-hours) by the emission factor of your local power grid. Each country's grid mix — the combination of coal, natural gas, nuclear, hydro, wind, and solar — determines how much CO2 is produced per kWh.
CO2 emissions per kWh depend on the energy grid mix of your country. Globally, 1 kWh of electricity produces about 0.475 kg of CO2 on average. In the United States it is around 0.42 kg CO2/kWh, in China about 0.58 kg CO2/kWh, in India roughly 0.71 kg CO2/kWh, and in countries like France (which uses mostly nuclear power) it can be as low as 0.06 kg CO2/kWh.
To calculate your electricity carbon footprint, multiply your monthly or annual electricity usage in kilowatt-hours (kWh) by the emission factor of your country's grid (kg CO2 per kWh). For example, if you use 500 kWh per month in the US, your monthly footprint is 500 × 0.42 = 210 kg of CO2, or about 2.52 metric tons of CO2 per year.
Both air conditioning and electric heating are major household electricity consumers. Central air conditioning typically uses 3,000 to 5,000 watts, while electric resistance heaters use 1,500 to 3,000 watts. However, heat pumps (modern efficient heating/cooling systems) use about 30-50% less electricity than resistance heaters. On a carbon basis, the actual CO2 produced depends on your grid's emission factor, but cooling in hot climates often results in higher annual emissions than heating in mild climates due to longer runtime.