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  • Category:
    Energy Efficiency
  • Published:
    March 25, 2016
  • Updated:
    February 5, 2020

LED vs. CFL Bulbs: Which Is More Energy-Efficient?

Confused about choosing between CFL bulbs vs. LED bulbs? Since 2014, government regulations have been pushing consumers to replace familiar incandescent light bulbs with more energy-efficient compact fluorescent lamp (CFL) and light-emitting diode (LED) bulbs.

Advances in both CFL and LED technologies have expanded consumer choice — yet make evaluating your options a little more complex. Knowing how different kinds of light bulbs stack up against each other will help you not only get the right lighting for any given space but also save energy in the process.

Understanding energy-efficient light bulbs

When considering a CFL vs. an LED bulb to replace an incandescent one, it helps to understand the basic differences in the three major light bulb technologies on the market today:

Types of lightbulbs: LED, CFL, Incandescent

  • Incandescent bulbs are the familiar pear-shaped or round screw-in light bulbs that have been marketed since Thomas Edison perfected the carbon filament bulb in 1879.
  • CFL (compact fluorescent lamp) bulbs are commonly manufactured as a spiral tube connected to a screw-in ballast or base. Newer technology replaces the curly light bulb with one that looks like the traditional incandescent bulb. They also now come in round and flame shapes.
  • LED (light-emitting diode) bulbs are a newer technology. Once only available as a longish tube, bulbs now come in nearly every shape and size, including flexible ropes for decorating.

CFL vs. LED bulbs

In the CFL vs. LED battle for energy efficiency, life span and cost, the winner is the LED bulb.

We’ve come a long way in energy-efficient light bulb technology. While incandescent bulbs remain on the market for now, the benefits of newer technology are driving the switch to LED bulbs. To understand the advantages of LED bulbs vs. CFL, or even incandescents, it helps to know a little bit about how they work.

In an incandescent bulb, electricity passes through a filament that gets so hot that it produces light. About 95% of the energy is wasted as heat, with only 5% of it going toward light.

CFL vs. LED bulbs

In CFL bulbs, an electric current flows between two electrodes at the ends of a gas-filled tube coated in phosphor. When energy hits this coating, it changes into light. The reaction takes between three and 30 seconds to start, which is why you experience a delay when you first turn on a CFL light.

LED bulbs produce light when energy is passed through a semiconductor in a way that produces visible light through electroluminescence.

Which is more energy-efficient: CFL vs. LED?

LED bulbs are much more energy-efficient than CFL and incandescent bulbs. They are hands down the best smart light bulb to use with your smart home system. When first commercialized, CFLs were heralded for their 25%-35% energy savings over traditional bulbs.

LED efficiency, however, has upped the ante. Comparing CFL vs. LED bulbs, LEDs with an ENERGY STAR® rating cut energy use by 75%. Both technologies are used in energy-efficient dimmer light bulbs.

Did you know? By 2027, widespread use of LEDs could save about 348 TWh of electricity, according to Energy.gov. That is the annual electrical output of 44 1,000-megawatt electric power plants and represents a savings of more than $30 billion at today’s electricity prices.

How much heat do CFL and LED bulbs give off?

LED efficiency is best because the bulbs waste very little energy on heat, concentrating electricity on the production of light. Incandescents waste the most energy. CFLs are not all that much better, releasing 80% as heat.

LED or CFL: Which bulbs last longer?

LED bulbs last longer than CFL bulbs. With 25,000 or more hours of life, an LED handily beats the  CFL bulb’s and incandescent bulb’s averages of 8,000 hours and 1,200 hours, respectively. Comparing CFL vs. LED bulbs, LEDs last much longer.

Did you know? The LED holiday lights you buy today will still be brightening the season 40 years from now, according to Energy.gov.

What kind of light do LED and CFL bulbs emit?

Light from LED bulbs is intrinsically directional, making it perfect for task lighting. LEDs  can be beamed to focus as downlights in kitchens, offices and bathrooms. Because they don’t get hot, LEDs are safer for use in tight spaces like closets and are more energy-efficient in refrigerators and other appliances.

Did you know? At least 500 million recessed downlights are used in U.S. homes, with more than 20 million sold each year. The Department of Energy estimates switching to CFL and LED bulbs in these fixtures could decrease downlight wattage use by 75% or more.

The difference between lumens and watts

Understanding the difference between lumens and watts can help when you evaluate your choices. Choosing light bulbs based on energy used measured in wattage is the familiar way to shop.

With advanced LED and CFL bulbs, however, the amount of energy used isn’t as important as the amount of light (lumens) provided. Manufacturers are labeling bulbs to make it easier to compare LED vs. CFL bulbs and choose the bulb that gives you the amount of light you need.

The difference between lumens and watts

This chart can help make changing from watts to lumens easier. We match the watts you’re familiar with against the ultimately more useful lumens metric. More lumens equals more brightness. When replacing incandescent bulbs, here’s a quick breakdown of how wattage translates to lumens:

  • Replace a 100-watt incandescent bulb with a 1,600-lumen bulb
  • Replace a 75-watt incandescent bulb with an 1,100-lumen bulb
  • Replace a 60-watt incandescent bulb with an 800-lumen bulb.
  • Replace a 40-watt incandescent bulb with a 450-lumen bulb.

Choosing the right light temperature

The last thing to consider is the temperature of the light emitted by different kinds of light bulbs. Light temperature, often seen as color, is measured on the Kelvin (K) scale.

The lower the Kelvin temperature, the redder the light. The higher the Kelvin temperature, the bluer the light appears. Candlelight is on the red end of the spectrum at about 1,900 K. Incandescent lights average 2,800 K. The daylight sun is about 4,800 K. LED and CFL light bulbs use filters to offer a range of light colors to fit the desired feel of a room or to support a room’s purpose.

Choosing a light bulb temperature

Warm light bulbs range between 2,700 K and 3,000 K and are comfortable for most living spaces. Cool, bright bulbs range between 3,500 K and 4,100 K and are good for brightening workspaces like kitchens and laundry rooms.

Natural daylight bulbs measure from 5,000 K to 6,500 K and are a bit too harsh for home fixtures. They are often used in commercial spaces and hospitals.

Moving toward energy-efficient light bulbs in your home

You have more choices than ever when it comes to lighting your home. And many of the best options are also energy-efficient. Along with cutting energy use, they offer durability and brightness, in shapes, sizes and colors for any application. If you haven’t made the move from incandescent, now is the time. Regulations aim at forcing you to change; better lighting choices make you want to.

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Comments ( 53 )

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Iain Fergusson - 6/4/2020

Seems to me that there is not an overwhelming case for replacing CFL’s with LED’s considering the higher cost and disputed life of the latter. It would take years even to break even.

Sanjeevani R - 9/14/2019

Great post describing the useful information about led bulbs vs cfl bulbs
Thanks for sharing this useful ideas. Looking for more.

Amit Chaudhry - 8/17/2019

LEDs and CFs both are energy efficient. However, LEDs are better than CFLs in terms of providing bright lighting. LEDs consume less energy than CFLs. The life span of a LED bulb is up to 50,000 hours or more, on the other hand a CFL bulb lasts up to only 5,000 hours. Apart from that when lightened, LED bulbs stay cool, whereas CFL bulbs heats up.

Shelby Strudler - 6/5/2019

Thank you! We couldn’t agree more about making the change. Feel free to share it with family and friends so that they can save energy in and around their homes too!

Led stadium - 12/15/2018

You done a great job about this category, I got the best and useful information and suggestions from this category. You made a good site and it’s very interesting one. Thanks for sharing the best information. Regards.

    Constellation Community Team - 1/23/2019

    Hey there, thanks for stopping by our blog! We’re glad our information helped.

Leds Universe - 10/29/2018

I have read your post it’s very informative and thanks for sharing the difference between led or cfl bulbs.This is a much appreciated post. Thank you for sharing your knowledge.

    Constellation Community Team - 1/23/2019

    Hello, thanks so much for checking our blog out.

livers - 10/24/2018

LEDs are nice, but I just love the way houseplants thrive with the CFLs.

    Constellation Community Team - 1/23/2019

    Hi Livers,
    Indeed, CFLs do provide supplemental light to plants if they do not regularly get sunlight!

pea - 10/23/2018

I’ve been told not to make a habit of turning standard fluoro lights on for short periods of time as they use a lot more energy than incandescents in turning on. Is this in any way true for the new CFL’s?
If so, this would give LEDs another advantage.
Either way it would be great to educate my frugal obsessions.

    Constellation Community Team - 1/23/2019

    Hi Pea, turning CFLs on/off frequently does not impact energy usage (energy star states that “While there is a brief surge in energy use when a CFL is turned on, with today’s starting technology, that surge usually lasts about a tenth of a second and consumes about as much energy as five seconds of normal operation.”) However, turning them on/off a lot can shorten their lifespan, so it depends. We hope this helps!

Leds Universe - 10/3/2018

Very amazing blog thanks for sharing your blog.

    Constellation Community Team - 11/7/2018

    Hi there, thanks for visiting!

Led stadium - 9/15/2018

Thanks for sharing your post it is very informative.

    Constellation Community Team - 11/6/2018

    Hi, thanks so much!

Chris - 6/15/2018

Great post, I completely agree with the observations made in the blog. LED lighting products is more energy efficient than CFL bulbs simply because they are based on better technology. Modern LED lighting products are surely more power efficient and human centric. Last year, I read a research paper that said that huge exposure to CFL can adversely affect human health. Thinking about the same anf after additional research, I completely renovated my house lighting with LED light bulbs. I bought 100 pcs (50 for home and 50 for my office) directly from a manufacturer named SeniorLED and ended up crossing the cost factor. The power efficiency is remarkable, so is the lighting quality. I think modern LED technology is really great, but not many LED manufacturers are focusing on developing healthy LED lights based on modern technology. Thank you for creating the awareness!

    Constellation Community Team - 7/16/2018

    Hi Chris, that sounds like a great research paper topic! Thanks for sharing, and good luck with your new LED purchases.

Leandro - 6/7/2018

Nice post, nice video, LED new technology and energy saving. Thanks for sharing this post.

    Constellation Community Team - 7/16/2018

    Hi Leandro, thanks so much!

Katrina Long - 6/3/2018

I have a question about the CFL (spiral) light bulbs. I had one go out above my bathroom vanity. (The light fixture holds two bulbs.) I assumed it had burned out. So I turned OFF the light switch controlling the light fixture to replace the “burned-out” bulb. As I was unscrewing the” burned-out” bulb, the bulb actually came back ON for a split second, then went back off. My immediate reaction was to determine that it had only loosened and that it wasn’t actually burned out. I screwed it back in and turned ON the switch. (Note that the light switch was in the OFF position when it flickered back on!) After I turned the light switch back on, the light bulb that I thought was burned out came on, first dimly, then it eventually brightened. Then it went dark again. Is this a common occurrence with CFL light bulbs? Do they have the ability to store and emit light when the electrical supply has been shut off? Or is there something going on in my electrical wiring to the light fixture that I need to address?

    Constellation Community Team - 7/16/2018

    Hi Katrina,
    We’d love to look into this for you, but for safety’s sake, this question would probably be better answered by an electrician. If you give your electrician a call, they should be able to give you more information about this subject or come out to your home to inspect your wiring!

Russell Rowe - 12/17/2017

And one more comment, for Constellation Community Team. I’ve now read through most people’s comments and every time your replies have been respectful, grateful, and never defensive! That’s very refreshing so thanks! 🙂

    Constellation Community Team - 2/28/2018

    Hi Russell, you’re very kind and we’ve updated the text. Thanks for keeping us accountable!

Pat Haughey - 11/21/2017

I live in a cold climate for 8 months out of the year. Why has no one ever talked about the heat a incandescent bulb gives off , that would reduce the cost of heating your home.

    Constellation Community Team - 2/28/2018

    Hi Pat, that’s a great observation! That certainly can tie into the cost of heating your home.

Cfl Manufacturing - 11/16/2017

I like CFL Bulbs because recycling CFLs keeps mercury out of the environment.

    Constellation Community Team - 2/28/2018

    Hey there, we totally agree! Thanks for adding to the conversation.

Make In India Trade - 10/17/2017

Nice article…Helpful information…

    Constellation Community Team - 2/28/2018

    Thank you!

d - 10/1/2017

One another thing… Never buy very cheap LED bulbs(e.g. from china) because they can have very simple and cheap inbuilt powersupplies, and in this case it can happen that the light will flicker on 50Hz, what lot of people can not see, but it can cause headache and tiredness. It is because they put too small buffer condensator( cuz it is cheaper) in the power supply and the output dc, what drives the LEDs, will be too waved, and will turn on and off the LEDs 50times in every second. It is easily fixable but just by experts.The other problem with these cheap LEDs that they are capacitive consumers in the electric circuit. In some type of situations, this can cause higher power bills. Buy from a trusted manufacturer.

    Constellation Community Team - 10/11/2017

    Hi D, that’s a good point, and a great tip when shopping for light bulbs. Thanks for sharing!

Nick - 9/28/2017

You state: ‘CFLs used 25-35% less energy than incandescent bulbs’. You should have said ‘CFLs use 25-35% of the energy used by incandescent bulbs’. This is a glaring error. The comprison chart you use supports my argument.

    Constellation Community Team - 10/11/2017

    Hi Nick, you’re absolutely right, and we’ve corrected the error in wording. Thank you!

Matt - 9/21/2017

There is yet another advantage to LEDs vs CFLs that nobody seems to mention: they are available in a much wider array of sizes and styles than CFLs. For instance, there are no satisfactory CFL replacements for small base bulbs such as flame tip chandelier bulbs or small globes. Before LEDs, there was no alternative to using inefficient incandescents in fixtures using these sorts of bulbs. But LED replacements in these sizes are both commonplace and work well. Given the number of fixtures that exist and use these sorts of bulbs (and the fact that such fixtures typically use multiple bulbs), the use of LEDs has the potential to result in HUGE savings in terms of electricity used for lighting.

    Constellation Community Team - 10/11/2017

    Hi Matt, That’s an excellent point! There are so many different light sources in a home that require different sized bulbs. LEDs offer great savings for your household in all ways. Thanks for the tip!

S. roosth - 8/16/2017

good info but quit putting the “Share” stuff on top of the tables…it’s aggravating and covers up the info

    Constellation Community Team - 11/1/2017

    Hi S., Thank you for your input, we’ve taken it to heart! This post and our newest infographics in blog posts moving forward will not have our share options when you roll over an image.

Ed Glowacki - 8/12/2017

I remember when CFL bulbs first came out they were relatively high priced compared to regular bulbs . Over the years their prices came crashing down , especially with subsidies . The last time I bought these bulbs I was able to purchase 6 60w equivalent bulbs at Costco for around $3.00 .
I understand the slight energy savings between the two , the only problem is the led are so much more expensive at sometimes $2.00 a bulb . In my honest opinion , the cost of the led bulbs just doesn’t ring up to savings that are the worth the purchase .
Although CFL bulbs do start up slower and are temperature sensitive I have had long lasting great luck with them . Another disadvantage with the CFL bulbs is that they do not last as long as the advertised time of ten years in off and situations , such as in a closet .
I feel that even with these drawbacks I will still be hesitant about paying $2.00 for light bulb .
I also feel that big business has an intentional focus on led bulbs because there is larger profits to made off of newer technology .
We are being forced to purchase bulbs which cost almost ten times as much to get minimal cost savings .
It is also getting harder and harder to find CFL bulbs as more and more retailers ,i.e. Walmart sell nothing but led bulbs .
Again as I said the average consumer is forced to spend more because we have no choice .
Another general concern is that CFL bulbs as well as regular fluorescent bulbs contain mercury . I understand the environmental impact but as long as you recycle them at stores such as Home Depot , the risk is minimal .
Of course all of this is only my opinion .

    Constellation Community Team - 11/1/2017

    Hi Ed, It’s great that the costs of CFL bulbs have lowered exponentially since they first came out! Hopefully LED will follow suit. Right now, both bulbs are much more energy efficient than a regular incandescent bulb, so both are an eco-conscious consumer’s dream. Though LED is more energy-efficient, they are more expensive — we here at Constellation definitely understand the cost stretch of investing in LED lights. But we’re happy just offering information and energy-efficient news to our customers and readers. We then leave it up to you! Thank you for adding in your opinion; we appreciate the conversation.

BRBD & sons - 7/31/2017

This blog has a many valid points about CFL and LED bulbs. For example LEDs emit very little heat. In contrast, incandescent bulbs release 90% of their energy as heat, CFLs release about 80% of their energy as heat, according to Energy.gov.

James Ruggles - 4/22/2017

Very well written article, but considering most led bulbs have a Power Factor of .5 they are actually consuming twice as much power than what is rated or charged by the power company. While you will save on the power bill the actual energy usage of a led bulb is double, making them very close to CFL performance.

    Constellation Community Team - 5/11/2017

    Hi, James. You raise a very valid point. From what I can tell, the Power Factor on most residential LED bulbs is still pretty low. Still, it’s something to keep in mind; ultimately, the decision is an individual one. It would depend on whether your priority is to save money on your energy bill, or to actively conserve energy. Here’s some more information on the topic. Thank you for adding your thoughts to the conversation!

Peter Bennett - 4/8/2017

The article neglects to mention the price of the bulbs. I found in my local Walmart that 1500 lumen LED (100w equivalent) are around $40 apiece. Over 15 years, this more than doubles the cost shown above. Who knows whether we will still be using the bulb in 15-25 years?

800 lumen (60W equivalent) are $1 each. I am not sure why, but these are certainly cost effective. I suspect they are being subsidized.

    Constellation Community Team - 4/21/2017

    Hello, Peter. Thank you for your comments. Yes, LED bulbs tend to be more expensive than traditional incandescents or CFLs. And, you raise a good point about whether or not we will be using these in ~20 years or if there will be an even better alternative. For now, though, we’re looking solely at the savings with respect to energy use. LEDs definitely use less energy than other kinds of bulbs with equivalent lumens. You might not wish to replace all of your bulbs with LEDs at the same time because of the cost, but we’re hopeful that perhaps people will gradually replace their traditional bulbs with energy-efficient alternatives like LEDs.

    Thank you so much for sharing your thoughts and comments. I really appreciate your input!

Dan - 3/19/2017

The statement about 500 million US homes having downlights must be a mistake. I don’t think that there are even that many people in the US. Good comparisons of lights though. In my experience CFL bulbs never had the the long life that was claimed, I am getting much longer life out of LEDs.

    Constellation Community Team - 3/21/2017

    Dan, thank you! You’re correct. I’ve changed the original post to say that there are 500 million downlights in U.S. homes, but not that there are that number of households. Thanks for the great catch! 🙂

    I’m glad to hear that you’re finding success with your LED bulbs, and thank you for making energy efficiency a priority!

Brihat Energy - 3/10/2017

Very informative blog.! LED lighting has more benefits that traditional Bulbs. Some of benefits are Long life , energy saving this helps in reducing electrical bills, durable, Ecologically Friendly, Zero UV Emissions.

    Constellation Community Team - 3/20/2017

    Thank you for sharing your thoughts! Yes, I agree that there are lots of benefits to LED lights, and I am so glad that it sounds like you’re thinking of using them. Be sure to check back on the blog often, because we’re always sharing additional tips and ideas for how you can save energy.

Michael Wingo - 2/28/2017

From my experience, the CFL bulbs save about 76% over incandescent while the newer LED bulbs save about 87% over incandescent. In comparing LED to CFL, the newer LED save approximately 42% over CFL. Older LED bulbs are generally not as efficient as the newest ones. Also, the LED bulbs I am familiar with are not long, but formed into the same shape as an incandescent bulb containing multiple, and tiny LED’s.

    Constellation Community Team - 3/3/2017

    Hi, Michael. I appreciate your taking the time to share your thoughts and insights. As technology changes and newer products hit the market, the specifics on the efficiencies of one type of bulb over another is bound to change, as well. However, I am so glad that you’re making the effort to find and use the most energy-efficient bulbs. Please check back with us for more information — we’re always working to provide insights into ways that people can be energy-efficient in all aspects of their home and business!

Darwin Crew - 8/11/2016

There is excellent information on this site and a lot of good comparisons between LED and CFL.

    Constellation Community Team - 3/3/2017

    Thank you for taking the time to comment. I am so glad that the information has been helpful to you. Please do check back on the blog again soon for more tips on how to manage energy use in your home or business. Thanks!

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