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?


led light bulbs

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.



8 thoughts on “Energy Savings Calculator: A simple, easy to use formula”

  1. Hi.
    Thanks for providing this info.
    I have always wondered just how much money I would save by converting to LED bulbs in my house.
    I’ve always been kind of skeptical about it, but now I see that there are some savings to be had.
    Do LED’s last as long as a regular bulb?
    Thanks again ~Jeremy

    • LED’s last anywhere from 10 to 20 times longer than regular bulbs, so you not only save on energy, but you save on bulb replacements as well. This can really add up to some big time savings. Thanks for visiting my page. 🙂

  2. Hi there my friend,

    Awesome website and fantastic idea to get the information and word out to everyone about LED lights. As they can save not only some cash but the environment also.

    As An Electronic Systems Engineer I can confirm that you calculation and formula are 100% correct.

    keep up the hard work and the brilliant information coming .

    • Hi Derek. Thank you so much for visiting my website and for your wonderful comments. I really appreciate the positive feedback. 🙂

  3. I think that one of the best things about led bulbs is that they don’t have the slow startup that plagues many CFL bulbs. Also, most people don’t realize that if a CFL gets broken, you are supposed to evacuate the entire house because they contain mercury gas! As someone else mentioned, the LED lights last forever, which makes them particularly well suited for places that are hard to get to (like vaulted ceilings) or rough-service locations like garage doors.

    • Hi Jeremy. Thanks for your comments. You are absolutely right about the hard-to-get benefit of LED lighting. Many people are using it in places where there is a lift required to get to them, and that alone will save a lot of money and labor. 🙂

  4. No doubt about it, LED lights save you a ton of money. They are certainly more expensive than old fashioned incandescent bulbs, but when you factor in their low energy usage, plus the fact that they last so much longer, they really are a very worthwhile investment.

    And the thing is, you only have to change them once. They last for years, so you won’t need to be getting the stepladders out to change failed bulbs every few weeks!

    • Hi Jim. Thanks for stopping by my page. The price of LED bulbs has come down so much that it’s not really that much more to buy them, and with the energy-savings and extra life, so much money can be saved. 🙂


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