Flipping a light switch may seem like it cannot have any real impact on the total energy use of a building or home. However, many people are not aware that more than 10 percent of the energy used in the average home goes toward lighting. That number jumps to about 20 percent in commercial buildings.
Why the difference? Lighting needs to be brighter in office spaces and are also used for longer durations than they are in a home. A typical small conference room will boast 10 or more standard T8 fluorescent light bulbs that cumulatively consume 320 watts of electricity per hour. In other words, a conference room will use a kilowatt-hour of electricity every three hours that they are operating. If they are left on for a week, they will use 56 kilowatt-hours and will have an energy cost for that one week of more than $6.00. It may not seem like much but think about how many conference rooms the state uses as well as how much those costs can add up to over a year.
Watch It Add Up
An average U.S. household has forty light sockets. If you consider one standard 60 watt light bulb, it will use one kilowatt of energy every 16 hours. Kilowatts are what measure the cost of your electric bill both at home and at work. So if one kilowatt costs 11 cents, you can have that single bulb run 16 hours straight for the cost of one kilowatt, or 11 cents. Eleven cents is really inexpensive right? By doing some simple math, you would find that lighting a home for 16 hours would cost you $4.40.
To go a step further, consider lighting a house for a week. One bulb would use about 10.5 kilowatt-hours at a cost of $1.15. But with all 40 lights shining for a week, you just spent $46.20. No one wants to spend that much money leaving lights on. A more realistic example would be leaving four bulbs on accidently for the duration of a year. Those four bulbs that are left on will cost you $240.24 over the course of the year. Amazing how those numbers add up over time!
So when you leave a room, whether at home or at work, remember to flip the switch.