Energy Savings Calculator: A simple, easy to use formula

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Do LED lights save money? How much energy do LED lights save? I’m sure many people have asked these questions, but aren’t sure how to figure it out. Below is a simple energy savings formula and an explanation of what the numbers mean and how to get them.


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First, you need to figure out how many watts your current bulb or fixture is.  Let’s use a 75 watt BR40 Incandescent flood for this example. Next, we figure out the wattage of the LED bulb we want to use. This BR40 LED bulb is 12.5 watts.  Then, we need to figure out how many hours they are used. If they’re in your kitchen and you’re in it a lot, let’s say for the example that they are used 6 hours per day, 7 days per week, 52 weeks per year. So that’s 6 times 7 times 52 equals 2,184 hours per year. Next, we need to find the annual kilowatt hours, so we just divide by 1000. Lastly, we multiply that result by the kilowatt hour (kWh) price.


energyThe average price per kWh varies by state, but according to this link from the U.S. Department of Energy, in California it is around $.18.  Most states are lower, but make sure you are looking at the current year’s numbers.


So our calculation would be: 75 minus 12.5 times 2,184 divided by 1000 times .18 = $24.57.  That’s $24.57 in annual energy savings for just that one bulb. If you have 10 bulbs in your kitchen you would save $245.70 per year on the energy that they use. Plus, the more hours you use them, the higher your energy savings would be.  If you substitute 4,000 hours in for your annual hours, your annual savings for that bulb is $45.00.


Using our example bulb, the BR40 LED bulbs are around $15.00 each. If they save $24.57 per year that’s $2.05 per month, so in 8 months the bulb is completely paid for by the energy it has saved!

Do LED bulbs save money?


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So if you’ve been wondering, “Do LED bulbs save money?” The answer is “YES!” It’s really a no-brainer to replace all of your lights with LED’s. I didn’t even touch on the air conditioning savings associated with LED bulbs, but you can read my blog on it if you’re interested.  The calculation above can be used for any bulbs or fixtures even if they’re not LED.




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