In the US, one kilowatt-hour (3.6 MJ) of electricity currently causes an average 1.34 pounds (610 g) of CO
2 emission. Assuming the average light bulb is on for 10 hours a day, a 40-watt bulb will cause 196 pounds (89 kg) of CO
2 emission per year. The 6-watt LED equivalent will only cause 30 pounds (14 kg) of CO
2 over the same time span. A building’s carbon footprint from lighting can therefore be reduced by 85% by exchanging all incandescent bulbs for new LEDs if a building previously used only incandescent bulbs.
In what country does one kilowatt-hour of electricity causes 1.34 pounds of CO 2 emission? How much CO2 emission would a 40-watt light bulb produce after 10 hours? A 6-watt LED left on for 10 hours a day will emit how much CO 2? How much can a building's carbon footprint be reduced by switching to LEDs?