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Do light dimmers really save energy?

By FPL Expert

Asked on: June 11, 2012 by Kathy M., Naples

Do light dimmers really save energy?

Dimming the lights can save a substantial amount of energy and may extend the life of the bulb. Modern light dimmers reduce the voltage to dim the lights in a much more efficient manner, so they have negligible energy losses unlike the dimmers of 40 years ago.  Dimmable compact fluorescent light (CFL) bulbs can save even more, but keep in mind that their dimming characteristics are often only high, low, and off.   For lights you do not dim, traditional CFLs are a true bargain. They use 75 percent less energy than standard light bulbs, and they last 10 times longer. The average CFL will save over $50 in electricity over the bulb’s lifetime. The substantial energy savings and long life cycle make CFLs a great choice for lights you use for several hours a day and for light fixtures in locations that make it difficult to switch out the bulb.  CFLs designed for outdoor use are also available and the savings can really add up for lights you leave on at night.    If you have been hesitant about buying CFLs because you don't like the color of fluorescent light, check the back of the package for bulbs with a warmer color temperature in the range of 2700-3000K.  For additional ways to save at home, check out our appliance tips at www.FPL.com/appliance.

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Comments [53]

  1. Michelle

    Isn’t it true that the CFL bulbs contain Mercury? If broken in the home that could pose a serious threat to our health. Not to mention all of the spent bulbs leaking Mercury into landfills.

  2. Charles Loughery

    IN Central Florida is changing from single pane windows worthwhile? How long would the payback period be?


    Thanks for the tip. I will be looking to install some dimmers real soon.

  4. Susan Nolan

    Our power company sent out free CFLs to help keep effiencey. They sent enough for our whole house. And they last longer. That was a double win!

  5. CJ

    CFL’s absolutely DO NOT last ten times longer than standard bulbs. In fact, they have not lasted ANY longer, and in some instances, they have lasted LESS than standard bulbs. Yet they cost, AT THE VERY LEAST, FIVE times more. In addition, they don’t put out the same amount of light, so you have to buy the higher watt bulbs, which cost more, just to get a similar amount of light of a standard bulb. Also, CFL’s decrease their light output before they finally give up the ghost. And if all that wasn’t bad enough, many of the CFL’s I’ve taken out because they quit had scorch marks all around the base of the glass part; which makes me believe they could be a fire hazzard. And, on top of ALL THAT, the only acceptable way to dispose of them is to take them yourself to the waste management facility, which takes time from my day and costs gas to go to/from there. So, where’s the cost savings? And who gets the savings? p.s. they also put out heat, just like the standard bulbs.

  6. Pat Hincken

    Only me here, so I am self regulated! I use surge protectors for all cable boxes & TVs when not in use, turn off by the switch on surge protector. I set my AC on 78 and unplug everything that I can when they are not in use-esp coffee pot, even the micro wave but just sometimes. I have had electric bills of $35 per month.
    When my granddaughters are here, not so much! We must teach the young ones to stop wasting energy. They think I am a wild women because I unplug their PCs, their cell phone plugs & hair utilities when not in use and so on.
    I am a true energy saver and it is not all that difficult to do.

  7. Joe M

    I don’t understand why people are having so much trouble with modern CFL’s.. I bought some for my whole place, and after 2 years haven’t had to replace a single one yet. They also come on instantly, no warm up period. The closest thing to a warmup is in the oldest ones I got (still working) and they still come on instantly, but at about 70% of their maximum brightness, then over the course of 15-20 seconds get to maximum brightness. I love that cause I use them in the living room and its great after a movie that our eyes aren’t killed by the sudden blinding brightness giving them a chance to adjust comfortably.

    They also don’t produce nearly as much heat as old bulbs which will equal savings on your cooling bill as well. I can walk up and touch these while they have been on after hours of use without burning myself. Try that with the old ones and you better have ice and a bandage ready. They also make them with protective covers that mimic the look of old bulbs if you don’t like the swirled look, or worry about breakage and mercury.

  8. richard

    I guess this article is about saving energy…
    not the potential hazards of CFL bulbs. And they don’t last very long.

  9. richard

    CFL bulbs SUCK!!!they burn out quickly, they are made in China and if you break one you have to evacuate the house… WHY are these problems not discussed! Energy savings big deal!!I’ll pay the extra few cents…

  10. Lila

    Not if you go to Walmart.I got a pack of two for only $8.00!

  11. Remguy


    Your information is good, your point is valid, but, wow, your delivery needs a little polish. Honestly, nobody likes to read opinionated, caustic remarks; it’s like a loud noise when you’re hung over or listening to two pre-teens overuse swearwords for the first time.

    Before you take offense, consider this: if you soften your delivery, you’re point will be much better received, both at home and at work. And in these forums.

    Thanks for your post, I found the information in it very useful – Remguy

  12. Linda Zilber

    Thanks for the news you are now sending

  13. David Segbers

    Ref: Dimmers save money.

    My Experience with CFL’s is that they cost more but last only a fraction of the time of traditional bulbs. The bulbs in my kitchen and other spot lights are slow to start in winter, up to two minutes before they are up to full light output.

    The bulbs in the laundry room last no more than two years.

    The cost to own is higher however they are much cooler to be near in summer.

  14. J. Luman

    When we found out that “our” government were going to require that we use the new mercury light bulbs, we began buying and storing the old bulbs in the different wattages that we use. The new bulbs give my wife a headache, are slow to come on, and heaven help if you break one! Call a HAZMAT clean-up crew. The new led lights seem to be a better answer, but our President has already committed the “green” bulbs to his cronies and supporters! Help correct the “Presidential delima” in the next presidential election!

  15. Herman R. Ouellette

    I must agree with those folks who say CFLs are not longer-lasting than incandescents.It has been my experience that I have had to replace too many to make it worth buying them.Dimmers work well in my house,and I’ve installed them where they were worth it. And I have used them for years.

  16. Elizabeth Hughes

    I disagree with all the hype about cfl bulbs being so much more efficient. I have found that many, if not all, of my incandescent bulbs have lasted a lot longer than the cfls. And, I don’t have to worry about mercury poisoning. The incandescents are much cheaper and you can find many of them made right here in the good old USA. Now, the newer, LEDs I am going to try in my kitchen spotlights – just as soon as one of my 8 year old – and going steady – incandescents burns out. The LEDs are pricey, but the light is much cooler than the floods, which for my kitchen would be a blessing. If they last as long as my current incandescents, then I’m way ahead of the game.
    Shut your house down once the temp/humidity level is uncomfortable; set the thermostat at 79-80 degrees and leave it there for the summer, even when we get one of our unusual “dry-cool” summer days. Been doing this for 8 yrs in my house – have the lowest elec. bill of everyone I know. And, my house is comfortable.

  17. Zorin

    I’ve had good luck with EcoSmart CFL lamps, as well as GE and Philips.

    The key is to not buy those unbranded ones you see in dollar stores; they are typically made as cheaply as possible and with little to no quality control. They may be inexpensive but will cost you more in the long run in the form of failed lamps, sometimes spectacular failures involving smoke and flame.

    Stick to name brands. Ecosmart, GE, Philips, Sylvania, etc. Avoid Lights of America, and anything without a brand. If a company isn’t willing to brand a product, that means they don’t stand behind the quality. Avoid!

  18. Dennis Kauser

    The figures on long life of CFL do not jibe with our experience. Most times they may not last as long as standard bulbs in real homes where lights are turned on and off frequently, thus are not close to cost effective. Where a light is left on all the time, it appears they do close to what is advertised. But in real homes, that is rare. They are safety hazards when used in stairwells as as they age, they are slow to come on. We replaced all CFLs with standard lights after finding this out. This negated any electricity savings for several years.

  19. Marta Reyes

    I think dimmers are a great choice for saving energy at home.

  20. Keith C. Cooper

    There are several types (Color ranges) of CFL. Use the “Daylight” style bulbs where you want a whiter light. These are great in the kitchen and bathrooms. If you find that CFL bulb are just not bright enough for reading, get the new 24w (100W eq.)which are very bright. You are still saving lots of wattage over the old 60w traditional bulbs and saving money, but will have a very bright light. I found these great for reading lamps. I believe more people will switch to the 24w bulb because it is the perfect fit to switching to CFL bulbs. I found that the CFL 12watt bulbs just where not bright enough.

    1. Gregory Schwarz

      I think that the energy used by a light with a dimmer being used is exactly the same – – – I agree that the bulb will last longer except that the useage is exactly the same as you are droping the power through the dimmer to the bulb – – – Therefore the useage is exactly the same – – – You can notice this as the dimmer will get warm as it is useing the energy drop on a resistor – – –



  22. Dave

    Being impressed with CFL’s years ago, I switched almost the entire house to them. In spite of their promised 7 year life span, about 1/3 failed within a few years, making them NOT cost effective. However, LED lights with a simpler structure should truly last a lifetime and will eventually become very competitive. I would NEVER consider going back to ancient filament bulbs which are basically tiny space heaters….

    ALSO those who worry about the mercury in tiny CFL’s might look at the large flourescents on the ceiling which I sjuspect contain mercury as well, and I know of no one getting sick from them in the last 70+ years of their use..

  23. Andrea

    Those new bulbs not only do not save electricity. Pennies maybe. They are so dim you have to use twice as many to see! Plus, they are very dangerous1 You need a hazmat team if they break and they are very bad for the envirnment. I hope one of the first things the new president does is take away this stupid law that tells people what kind of lightbulb they have to buy! None of their business. The new ones are too expensive also! So there is no savings at all!

  24. jim lambert

    Nice that dimmers save energy; hence $’s, but we primarily use them to create a pleasing ambiance.

    Additional narketing approach, eh?

  25. Bonnie

    I did not save anything by buying CFL bulbs. As a matter of fact, by them being twice as expensive to buy (or more)and claiming that they last 5 to 7 years,they not only didn’t save me anything, I would say it cost more.They didn’t last past 2 years, not any of them, some not even a year. So that alone escalates the cost. Besides the fact that when we buy them, we are only supporting other countries because none are made here. I will find the ones that are made here (traditional bulbs) and use them from now on.

  26. Bob McLeran

    I presume the new LED bulbs (available in various color temperatures from warm to cool white) save even more over the CFLs. They’re still relatively expensive, but the price is coming down and they’re available in many different styles and some are dimmable.

  27. Michael Cummings

    I’m amazed FPL is still pushing CFL bulbs with no mention of LED options given the toxic mercury the CFL’s contain. It would be much more responsible to promote the latest LED bulbs that do not have the negative environmental impacts and use very little electric.

  28. James Mathews

    While some CFL bulbs now claim “instant on”, even they seem to be less bright for enough time to be noticible. My kitchen had 9 70 watt ceiling incandesant floodlights. I replaced all but the one over the island with CFLs, so that the light in the center of the room would be truely “instant on”, and the rest would be doing their full job by the time anyone adjusted to the sudden burst of light from the one bulb. It seems to be a much better compromise than all CFL, even the current lot of “instant on” CFL bulbs.

  29. Robert Crim

    Since the voltage drop in an incandescent lamp has to be wasted by the resistance, I must question whether the dimmer cuts down the energy bill; however, it is true that reducing the voltage through the filament by ten per cent will extend the life of the bulb by years. Indeed, there are incandescent lights at Thomas Edison’s winter home in Fort Myers, Florida, which were installed by Edison, himself, around 1915 (they are run on DC at even lower voltages).

    DO NOT TRY THIS WITH A FLUORESCENT LAMP, SINCE IT COULD CAUSE A FIRE!!! Make certain you know what kind of light bulb you have.

  30. barbara

    We switched to CFL bulbs as soon as they were available, and find that they are not lasting anywhere near as long as they were touted. Standard bulbs on dimmers last much longer, and are much more versatile.

  31. Steve

    It’s worth noting that there are differences in dimmers. The cheap “rheostat” type are inefficient because they dissipate heat when lowering the voltage to the lamp whereas the modern “SCR” dimmers are much more efficient as what they are doing is rapidly turning the lamp on and off.

  32. Ross

    Incandescents are going away. CFLs are nice but contain mercury and are hazardous when dropped or disposed, and of course are not dimmable as noted.

    The best choice is LED lighting. They are 100% dimmable, save you more on your electricity bill than even CFLs, and are completely non-hazardous. Prices are dropping fast and getting close to CFLs. Check them out at your local home depot or walmart.

    1. Al Hajducko

      The advertised lifetime of CFL bulbs (and LED bulbs also, I suspect) is greatly exaggerated; if you read the fine print, the “5 year” or “7 year” bulb will only last that long if you use it 3 hours a day or less.

    2. Al Hajducko

      Read the box carefully – all LED bulbs (especially the “inexpensive” ones) are NOT dimmable.

  33. Joseph Butte

    I wish you would include the hazards of CFL bulbs. It is recommended by the EPA, if you break a CFL bulb you must turn off the AC and leave the house for twenty minutes to allow the MERCURY to settle. Then you must put on a dust mask and vacuum up the bulb using a HEPA filter. Otherwise the Mercury will just be blown back into the air.
    It is hard for me to understand why these warnings are not on the package of bulbs or why people who recommend these types of bulbs ignore the hazard.

  34. Flo

    CFL bulbs suck! They are constantly blowing out,the light is harsh and are expensive too.

    I would rather have regular old bulbs that last forever.

  35. Walter Graef

    You fail to mention the disposal problems associated with CFLs.

  36. John

    The value of CFL’s is questionable. I have tried various CFL’s for their low heat properties and while they excel in this characteristic, the life span has been poor. I have had very few last more than 5 years, yet I have many incandescants on dimmers that are easily 12 years old. When you factor in the purchase price with the electricity savings, it is maybe break even at best. The so called “life span” of CFL’s are assumed to be much greater than incan’s to get that cost savings. When they fail prematurely, you lose money.

  37. Allen Wolk

    You have not mentioned “incandescent” by name, and failed to mention anything about dimming LED “bulbs” at all! Please elaborate more about energy savings and money savings. Thank you.

  38. Dale

    The thing is, I have yet to find a CFL bulb that comes on when you apply power. When I want light I don’t want to wait for a bulb to “warm up” before delivering light. And these bulbs are way too expensive for the initial cost.

  39. Grey Miller

    You should also mention that different bulb types require different dimmers. You can’t just put a cfl in or especially a led bulb and use the same dimmer.

  40. Matt Chrycy

    Dimming is the way to go, save money stay cool!

  41. Dave Z

    We moved to FL last Oct. and our e- bill
    averaged $75. (we are very conservative)
    When june and july hit, the bills went
    to $135 and $140 ! The only thing that changed
    was the weather, so I guess we will be
    raising the temperature in the summer
    months from now on. Reading other posts
    made me aware it wasn’t just us, or some
    unidentified problem.

  42. James Donnelly

    What’s with all the hype about CFLs, they suck, they have mercury in them and the light emitted gives me a headache in five minutes. With the lower cost of LEDs now available and the fact they use much, much less energey than even CFLs and are also available in dimmable as well as outdoor and indoor floods. They have no mercury, last a lot longer, burn much cooler (almost no heat) and because they burn so cool thay can be lightly spray painted to soften the glow.

    Get with it…..



  43. Tony

    Plus they keep the heat down. My kitchen has 8 recessed floodlights running them would always make the room warmer thus my AC worked harder. Now I keep them about 50%or lower and the room is cooler and my electric bill lower.

  44. Barbara Anne Drabek Doyle

    I like the information you provide. I bought new enery effiencet LED light blubs for most of my lights and did not see that as an option when I did the survey.

  45. Peter Costello

    I wouldn’t mind paying a bit more for CFL lights if they were reliable- they are NOT. They consistently fail more frequently than incandescents. It makes no sense at all to pay a lot more for a product that does not deliver.
    The advertised life of CFLs does not reflect my experience. Green is fine if it makes economic sense.

    1. Shawn

      They do fail early, a lot are dead right out of the box. They do still save money and if you look many come with a Warranty for so many years, so you can replace many for free. Just read before you buy and save your receipts. The my Lowe’s card should make it easier to keep track. I’d recommend writing the purchase date or a code to match the receipt right on them.

  46. Alex

    We use CFLs everywhere possible (except inside the oven), and some are even dimmeable. We pay 50% or less in electricity than our neighbors. They do work. We also have dimmers for lights that we don’t need 100% all the time including some CFLs, and lower power 25W for halogens when possible. … keep the lights on, but be smart about your lamps!

  47. Tom Morris

    These CFL bulbs do not last 10 times as long as regular bulbs,maybe only about 4-5 times as long, and I have been using them for many years.
    They do cost much more than a regular bulb, and there are issues with disposal which are not insignificant, and are not priced into the equation.
    The real savings will come when the LED bulbs only cost as much as a CFL, and provide the same or more light for the money.

  48. David

    Fantastic post. Dimmer switches are fantastic. Lowers your bills and allows you to set any lighting mood you want. Who knew seduction was so easy?


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