LED vs. CFL: Future of the light bulb
Posted by Joshua Prieto on Nov 16th 2014
LED and CFL have become household acronyms, but if you didn’t know what either of them stood for, don’t worry, many don’t. So when it comes to deciding whether to buy an LED light bulb or a CFL light bulb it’s not surprising that most of us make a less than an educated guess on what to buy. After reading this post you’ll have a clear idea of which technology to choose from (as well as what the acronyms stand for).
The Compact Florescent Lamp (CFL)
Regular fluorescent lamps, CFL’s origin, have been around for quite some time; in fact the first florescent light was created in the 1890’s. The first compact florescent was created in 1976 which is relatively recent, but it still creates light in much the same way normal florescent lights do. Electrons bound to mercury atoms are excited to a point that it radiates ultraviolet light, as the atoms reduce to a lower energy level they hit a fluorescent coating on the bulb which will then produce visible light. This process not only creates visible light, but a good amount of heat as well.
The Light Emitting Diode (LED)
An LED lamp creates light in a much different way than a CFL. Light emitting diodes are semiconductors (aka solid-state lighting) that when given enough voltage creates light. This is done by having electrons recombine with electron holes (the opposites of electrons) which release energy in the form of light. This process is significantly more efficient than CFLs as well as less hazardous to the environment. With a brief understanding of the technology behind CFLs and LEDs let’s take a look at five categories of comparison and determine which technology wins out the other.
Upfront cost of LED vs. CFL
In general, an LED light bulb will cost more than a CFL. Prices will vary from store to store and brand to brand, but at this point an LED’s price will be around twice the price of a CFL. The reason for the larger costs of an LED bulb has to do with the expensive materials used, highly skilled labor, industry specific parts, and the integration of highly sophisticated technologies.
Check out this manufacturers’s video to see the production of an LED light.
CFLs, on the other hand, have a cheaper materials cost, labor has been highly atomized with less skilled labor, and the technology is not as sophisticated to reproduce, making the overall cost to produce a CFL lower.
You can get a good idea of how CFLs are made in this manufacturer’s video.
One thing driving the progression of LED lights and ultimately bringing the cost of LEDs down every year is called Hait’z Law. This scientific law is similar to Moore’s law in the computing world. LED technology will continue to reduce in price and increase in efficiency because of its ability to double the amount of transistors on a given integrated circuit every 18 to 24 months. It means that roughly every two years the cost to produce LED light will drop in half and the efficiency of those lights will double! For now, CFLs will remain the cheaper option, but in the near future LEDs will take that spot.
Energy Efficiency of LED vs. CFL
Haitz’s law shows us that the efficiency of LED technology doubles every two years, but where is that efficiency in comparison to CFLs today? On average a CFL bulb uses less than 15 watts and costs about $75 dollars in electricity in one year. An LED bulb uses around 8 watts of power and costs about $30 dollars in electricity in one year. Even though LED light bulbs cost more upfront the additional cost compared to a CFL is usually recouped plus more within a year of use.
The Longevity of an LED vs. CFL
The best light bulbs are the ones you forget about. LEDs have an average lifespan three times greater than that of a CFL. Typical running time for a CFL is from 6,000 to 15,000 hours where LEDs have a running time of 50,000 hours or more. There is also often a significant variance in runtime hours of a CFL because its lifetime is decreased every time it is turned on and off. This is not the case for LEDs which gives an LED light further value knowing that it will last three times longer and doesn’t receive a reduction in lifetime as it is turned on and off.
The Quality of Light of an LED vs. CFL
There are a couple ways to measure the quality of light coming from an artificial light source. One is more of a preference rather than quality of light, but it is called the Kelvin Color Temperature Scale. Kelvin measures the blue or yellow hues that can be found in a typical white light (color temperature only measure the look of the color and not the heat it gives off). Again it is a matter of opinion on which color temperature you enjoy most, but a white with a bluer hue to it is often called a cool white, and a light with a yellowish hue is often called a warm light. Somewhere in the middle is what is called natural white or pure white and this color on the Kelvin scale is usually closest to sun light. Both CFLs and LEDs can be found in each color temp and the differences in color temperature vary more between manufactures than actual lighting technology. The scale below gives you an idea of different lighting technologies and what their color temps can range from. LEDs and CFLs can obtain the cool white, natural white, and warm white colors on the scale. Another measure called the color rendering index (CRI) measures a light sources ability to show the authentic colors of objects as if they were standing in a natural light source like the sun. The scale ranges between 1 and 100, 100 being the color rendering of the noonday sun and 0 being an inability to distinguish any color at all. CRIs of fluorescent lights range from 50 on average to 90 for high-end, tri-phosphor types. A standard CRI for an LED light usually stands in the 80s, but some manufacturers have bragged CRIs up to a 98. Both LEDs and CFLs are able to give off a high quality light that is several times better than incandescent lights. When it comes to light quality, LEDs and CFLs, are near equals.
The range of applications LEDs have over CFLs
If we talk about the limitations of LED technology you’ll find that there is one large flaw that will hinder its application in the future if becomes unresolved. It is called efficiency droop and it is a decrease in how well an LED will produce visible light as electrical current increases. There has been several suggested solutions to efficiency droop, increasing the number of chips held in one bulb is one of these solutions, but solving the problem entirely would help to reduce the cost to produce LEDs and open up further applications in the industry. Even with LED technologies greatest flaw the applications are limitless and it makes CFL technology feel archaic and trivial. Smarter lighting systems that are controlled by sophisticated computer programs are already being used to further reduce energy consumption which is largely due to the use of solid-state lighting. Even an experimental application that transfers wireless data through light is accomplished through LED technology. If you’re interested in how light can transfer wireless data take a look at the following video! The drawbacks of CFLs: environmentally unfriendly mercury, an inability to be used in extreme temperatures, a reduced lifespan each time it is turned on and off, seriously hinder the applications the technology can be used in. It really only has one application, to illuminate, and that can be accomplished by a far superior technology.
LED vs. CFL: The Winner
By now I hope it is clear what the future of the light bulb is. CFLs may seem like the affordable route to take at the moment, but a deeper analysis shows them to be more costly in replacements and energy consumption. The quality of light of a CFL can currently keep up with that of an LED, but its ability to provide that quality of light diminishes each time you turn the light off and back on. Lastly, CFL technology can only benefit us as a light source, where LED lighting can provide us with much more opportunity. LED, you are the winner!
Questions or comments about LED lights?
We covered a lot of information in this post and so you may still have questions or comments about LED lights. Birddog is a lighting company, and each year our focus has become more centered on LED lighting. If you have a question about lighting, more than likely we’ve found the answer. Give us call, email us, or leave a comment. We’d love to hear from you!