Incandescent light bulbs had a good run, but with the Energy Independence and Security Act (EISA) of 2007 now in its final phase, you’ll probably begin to notice that it’s getting harder and harder to find traditional incandescent light bulbs in stores.
In a nutshell, EISA has taken a three year approach to converting the United States to energy-efficient lights by prohibiting the manufacturing or importing of non-compliant incandescent light bulbs.
- January 2012 – 100-watt bulbs banned
- January 2013 – 75-watt bulbs banned
- January 2014 – by year end this year 60- and 40-watt bulbs will be banned
You might still see some of these bulbs on store shelves as it isn’t illegal to sell current or leftover inventory, but over time they will all disappear. But that’s not a bad thing. In fact, it will help American save a lot of energy and money.
How much can you save by switching your household to energy-efficient bulbs? Well, let’s take a look. We need three things to determine the cost of light usage and the potential for savings when switching to energy-efficient lighting:
- Amount of electricity used
- Cost of the electricity
- Time the lights are turned on
Amount of Electricity Used
We’ll need to begin with the amount of light bulbs in a home. According to a recent survey, the average American household uses 47 light bulbs.
Now, these bulbs might have varying wattages from 100 watts down to 25, but for the sake of easy math and comparisons, let’s assume that we are using all 60 watt bulbs.
Total Light Wattage = 47 bulbs X 60 watts = 2,820 watts
That’s a lot of wattage! Now let’s take a look at the wattage if all 47 lights are CFL bulbs or LED bulbs at the equivalent brightness of 60 watt incandescent bulbs.
| All bulbs deliver equivalent brightness | Single bulb wattage | Wattage used for whole house |
| Incandescent bulbs |
60 watts |
2,820 watts |
| CFL bulbs |
14 watts |
658 watts |
| LED bulbs |
9.5 watts |
446.5 watts |
As you can see, there is quite a difference in the wattage between energy efficient bulbs and incandescent bulbs. In other words, switching to CFL or LED bulbs would save A LOT of energy. And as I’m about to show you, this will, in turn, save a lot of money!
Cost of Electricity
The average cost of electricity in the United States is currently 11.88 cents per kilowatt hour (kWh) (for a more accurate cost, you can check your last billing statement for your cost per kWh), meaning if you used 1,000 watts of electricity for an hour, it costs you 11.41 cents.
Time that Lights are Turned On
The amount of time the lights are being used can vary quite a bit from home-to-home, but let’s pretend, for the sake of this example, that each of us use our lights for 5 hours a day. That’s 30 days in a month (on average), for 5 hours a day.
5 hours X 30 days = 150 hours
Now that we have all of the necessary factors, we can calculate the difference in cost of using traditional incandescent light bulbs versus energy-efficient CFL and LED light bulbs. The formula for this is below:
kW used X (Cost per kWh) X Hours Used = Monthly Lighting Costs
Remember, a kilowatt (kW) is 1,000 watts, so we divide our wattage by 1,000 for this formula.
Monthly Cost of Using Incandescent Light Bulbs
2.820 X $0.1188 X 150 hours = $50.25
Monthly Cost of Using CFL Bulbs
0.658 X $0.1188 X 150 hours = $11.73
Monthly Cost of Using LED Bulbs
0.447 X $0.1188 X 150 hours = $7.97
If, in this scenario, I switched 47 incandescent light bulbs to LEDs, I could save around $42.28 each month. That really adds up over the course of a year, and the savings continue to grow over many years.
Article appearing courtesy Xcel Energy Blog.
