Lighting Comparison: LED vs Fluorescent and CFL

Do you wonder what’s better: fluorescent lights (including compact fluorescent lights, or CFLs) or light emitting diodes (LEDs) ? Well here’s a head- to-head comparison of the two followed by an in-depth discussion of each technology in turn.

Fluorescent (or CFL) What is a Fluorescent L ight or a CFL? Fluorescent light bulbs are a specific type of gas-discharge light (also known as a high intensity discharge, HID, or arc light). CFL is an acronym that stands for compact fluorescent light . Standard fluorescent lights are available in tubes (generally 48 to 84 inches in length). CFLs are much smaller. They are still tubes but they are, as the name implies, “compact.” CFLs were designed to replace standard applications for incandescent bulbs as they are both more efficient and longer lasting.

Fluorescent bulbs produce light by converting ultraviolet emissions with a fluorescent coating on the inside of the tube. UV radiation is generated in the first place by an electrical charge that is run through th e inert mercury glass internal to the bulb. The gas is excited by the electricity and releases ultraviolet radiation as a consequence. Fluorescent lights require ignition, which is typically provided by a voltage pulse or a third electrode (an additional metal part) internal to the bulb. Starting is relatively simple with small tubes but c an require significant voltage with larger lights.

Fluorescent light bulbs previously required a “warm-up” period in order to evaporate the internal gas into plasma, but now there are several near-instantaneous starting technologies for fluorescent light (those include “quick-start,” “instant start,” and “rapid-start”). Additionally, as the light heats up it requires additional voltage to operate. Voltage requirements in fluorescent bulbs are balanced by a ballast (a magnetic device in older bulbs and an electrical one in newer fluorescent technology). As the fluorescent light ages, more and more voltage is required to produce the same amount of light until eventually the voltage exceeds the fixed resistance provided by the ballast and the light goes out (fails). Fluorescent lights become less and less efficient over time because they must use more and more voltage to pr oduce the same lumen output as the light degrades.

What’s the Upside to Fluorescent Lights? Fluorescent technology has been around for more than 100 years and it generally represents a high efficiency way to provide lighting over a vast area. The lights are much more efficient as well as longer lasti ng than incandescent bulbs, however, they fail in both categories when compared to LED.

What are the Major Deficiencies in Fluorescent Lights? Among the deficiencies in fluorescent lighting are the following:

Fluorescent lights contain toxic mercury. Mercury, as well as the phosphor inside the bulbs, are hazardous materials that present a waste disposal issue at the end of a light’s life. Broken bulbs release a small amount of toxic mercury as a gas and the rest is contained in the glass itself. Fluorescent lights age significantly if they are frequently switched on and off. Typical lamp life for a CFL is about 10,000 hours but this can degrade as a consequence of frequent switching (turning on and off). Burning life is extended if lamps remain on continuously for long periods of time. It’s worth thinking about in the event that you are using CFLs in conjunction with motion sensors that frequently activate and time out. Fluorescent lights are omnidirectional . Omnidirectional lights produce light in 360 degrees. This is a large system inefficiency because at least half of the light needs to be reflected and redirected to the desired area being illuminated. It also means that more accessory parts are required in the light fixture itself in order to reflect or focus the luminous output of the bulb (thus increasing unit costs). What are the Minor Deficiencies in Fluorescent Lights? Among the minor deficiencies in fluorescent lighting are the following:

Older fluorescent lights have a brief warm-up period . Once the arc is ignited it melts and evaporates metal salts internal to the device. The light doesn’t arrive at full power until the salts are fully evaporated into plasma. This is corrected in many newer models that utilize “rapid start” or similar technologies. Fluorescent lighting emits a small amount of UV radiation. Ultraviolet light is known to cause fading of dyed items or paintings exposed to their light. Fluorescent lights require a ballast to stabilize the light. In the event that there is a minor flaw in the ballast the light may produce an audible hum or buzz. Where are Fluorescent Lights Commonly Used? Common applications for fluorescent lighting include warehouses and schools or commercial buildings. CFLs are also used as a replacement for incandescent lights in many residential applications.

LED Lighting: What is a Light Emitting Diode (LED)? LED stands for light emitting diode

. A diode is an electrical device or component with two electrodes (an anode and a cathode) through which electricity flows - characteristically in only one direction (in through the anode and out through the cathode). Diodes are generally made from semi-conductive materials such as silicon or selenium - solid state substances that conduct electricity in some circumstances and not in others (e.g. at certain voltages, current levels, or light intensities).

When current passes through the semiconductor material the device emits visible light. It is very much the opposite of a photovoltaic cell (a device that converts visible light into electrical current).

If you’re interested in the technical details of how an LED works you can read more about it here .

Benefits of led lighting vs fluorescent tubes What’s the Major Upsid e to LED Li ghts? There are four major advantages to LED lighting:

LEDs have an extremely long lifespan relative to every other lighting technology (including fluorescent lights). New LEDs can last 50,000 to 100,000 hours or more. The typical lifespan for a fluorescent bulb, by comparison, is 10-25% as long at best (roughly 10,000 hours). LEDs are extremely energy efficient relative to every other commercially available lighting technology. There are several reasons for this, including the fact that they waste very little energy in the form of infrared radiation (much different than most conventional lights to include fluorescent lights), and they emit light directionally (over 180 degrees versus 360 degrees, which means there are far fewer losses from the need to redirect or reflect light). Very high light quality Very low maintenance costs and hassle What are Minor Upsides to LED Lights? In addition to the major a dvantages, LED lights also offer several smaller perks . These include the following:

Accessories: LEDs require far fewer accessory lamp parts. Color: LEDs can be designed to generate the entire spectrum of visible light colors without having to use the traditional color filters required by traditional lighting solutions. Directional: LEDs are naturally directional (they emit light for 180 degrees by default). Size: LEDs can be much smaller than other lights. Warm-Up: LEDs have faster switching (no warm-up or cool-down period). What’s the Downside to LED Lights? Considering the upsides, you might think that LED lights are a no-brainer. While this is increasingly becoming the case,

there are still a few trade offs that need to be made when you choose LED.

In particular, LED lights are relatively expensive. The up-front costs of an LED lighting project are typically greater than most of the alternatives. This is by far the biggest downside that needs to be considered. That said, the price of LEDs are rapidly decreasing and as they continue to be adopted en masse the price will continue to drop. (If you received a proposal for LED lights that just costs too much, don't give up hope. Value engineering can help.)

Where is LED Commonly Used? The first practical use of LEDs was in circuit boards for computers. Since then they have gradually expanded their applications to include traffic lights, lighted signs, and more recently, indoor and outdoor lighting. Much like fluorescent lights, modern LED lights are a wonderful solution for gymnasiums, warehouses, schools, and commercial buildings.

They are also adaptable for larg e public areas (which require powerful, efficient lights over a large area), road lighting (which offer significant color advantages over low and high pressure sodium lights), and parking lots. For an interesting take on the history of street lighting in the United States read here .

Further Qualitative Comparison What’s the Difference Between Fluorescent and LED Lights? The two different technologies are entirely different m ethods of producing light . Fluorescent bulbs contain inert gas within the glass casing while LEDs are a solid state technology. Fluorescent lights produce UV radiation and then convert it into visible light through the use of a phosphor coating inside the bulb. LEDs emit electromagnetic radiation across a small portion of the visible light spectrum and don’t waste energy by producing waste heat or non-visible electromagnetic radiation (such as UV). There is such a thing as an IRED (infrared emitting diode) which is specifically designed to emit infrared energy.

Why Would LEDs Put Fluorescent Lights Out of Business? In the last few years LED efficiency has surpassed that of fluorescent lights and its efficiency improvements are progressing at a much more rapid rate. Further, f luorescent lamps require the use of a ballast to stabilize the internal current that produces light. When the ballast has a minor imperf ection or is damaged, the light can produce an audible buzzing noise. Other shortcomings include the following:

Fluorescent lights can cause retrofit problems due to their elongated shape. Fluorescent lights can present waste disposal issues due to their reliance on mercury. Fluorescent lights are non-directional, meaning that they emit light for 360 degrees. As you might expect, a large portion of this light is wasted (for example, that portion that is directed at the ceiling). Why would LEDs Put Compact Fluorescent Lights (CFLs) Out of Business?

As good as fluorescent light efficiency has become, LED is better (and continues to improve at a more rapid pace). As long as fluorescent lights last, LED lights last much longer. Further, fluorescent lamps require the use of a ballast to stabilize the internal current that produces light. When the ballast

has a minor imperfection or is damaged, the light can produce an audible buzzing noise. Other shortcomings include waste disposal issues (due to CFL's reliance on mercury), and non-directional light generation. Non-directional light generation is a bigger deal than you might think. For example, light that is being directed at the ceiling rather than the room is wasted light. Therefore, CFL (as well as the related standard fluorescent bulbs) might have good “source efficiency” (i.e. it looks good on paper), but will fall short of LED when it comes to the more important measure: “system efficiency” (actual efficiency in real world applications).

Incandescent Lighting vs Light Emitting Diode (LED) Comparison Correlated Color Temperature LEDs are available in a wide range of color temperatures that generally span from 2200K-6000K (ranging from yellow to light blue).

Fluorescent light is available in a range of CCT values that can be adjusted by changing the amount of phosphor inside the bulb. Typical values range between warm white at 2700K to daylight at 6500K depending on the lighting requirement.

WINNER: -

CRI CRI for LED is highly dependent on the particular light in question. That said, a very broad spectrum of CRI values is available ranging generally from 65-95.

Typical CRI values for fluorescent light are between 62 and 80. This is fairly good color rendering but it leaves room for improvement when compared to LED.

WINNER: LED

Cycling (Turning On/Off) LEDs are an ideal light for purposely turning on and off because they respond rather instantaneously (there is no warm up or cool down period). They produce steady light without flicker.

Fluorescent lights exhibit a short delay when turning on. Older fluorescent models actually required a significant warm up period before the tube would light but this has been improved with newer, rapid-start fluorescent lights. Possible failures or delays in the start-up process are typically due to faulty starters, transformers, or ballast. Fluorescent bulbs may also flicker, display swirling or pink light, light at the ends of the tube only, or cycle on and off as the bulb reaches the end of its useful life.

WINNER: LED

Dimming LEDs are very easy to dim and options are available to use anywhere from 100% of the light to 0.5%. LED dimming functions by either lowering the forward current or modulating the pulse duration.

Newer CFL bulbs can be dimmed very effectively (down to about 15% of their normal light) while older fluorescent bulbs are often not suitable for dimming. If looking to dim a fluorescent bulb, make sure that you choose a ballast that is rated for dimming.

WINNER: LED

Directionality LEDs emit light for 180 degrees. This is typically an advantage because light is usually desired over a target area (rather than all 360 degrees around the bulb). You can read more about the impact of directional lighting by learning about a measurement called “useful lumens” or “system efficiency.”

Fluorescent light is omnidirectional meaning it emits light for 360 degrees, requiring fixture housings or reflectors to direct the emitted light.

WINNER: LED

Efficiency LEDs are very efficient relative to every lighting type on the market. Typical source efficiency ranges 37 and 120 lumens/watt. Where LEDs really shine, however, is in their system efficiency (the amount of light that actually reaches the target area after all losses are accounted for). Most values for LED system efficiency fall above 50 lumens/watt.

Fluorescent and CFL lights are very efficient compared to incandescent lights (50-100 lumens/watt source efficiency). They lose out to LEDs principally because their system efficiency is much lower (&lt;30 lumens/watt) due to all of the losses associated with omnidirectional light output and the need to redirect it to a desired area.

WINNER: LED

Efficiency Droop LED efficiency drops as current increases. Heat output also increases with additional current which decreases the lifetime of the device. The overall performance drop is relatively low, however, when compared to fluorescent lights.

Fluorescent lights also experience efficiency losses as the device ages and additional current is required to achieve the same lighting output. Efficiency losses are greater and the degradation time shorter in the case of fluorescent bulbs.

WINNER: LED

Emissions LEDs produce a very narrow spectrum of visible light without the losses to irrelevant radiation types (IR or UV) associated with conventional lighting, meaning that most of the energy consumed by the light source is converted directly to visible light.

Fluorescent lights actually produce primarily UV radiation. They generate visible light because the bulb is coated with a layer of phosphor which glows when it comes into contact with UV radiation. Roughly 15% of the emissions are lost due to energy dissipation and heat.

WINNER: LED

Ultraviolet LEDs - NONE

Fluorescent lights produce primarily UV radiation. They generate visible light because the bulb is coated with a layer of phosphor which glows when it comes into contact with UV radiation. Although most UV radiation stays within the bulb, some does escape into the environment which can potentially be a hazard.

WINNER: LED

Failure Characteristics LEDs fail by dimming gradually over time.

Fluorescent lights can fail in a number of different ways. Generally they exhibit an end-of-life phenomenon known as cycling where the lamp goes on and off without human input prior to eventually failing entirely.

WINNER: LED

Foot Candles Foot candle is a measure that describes the amount of light reaching a specified surface area as opposed to the total amount of light coming from a source (luminous flux).

LEDs are very efficient relative to every lighting type on the market. Typical source efficiency ranges 37 and 120 lumens/watt. Where LEDs really shine, however, is in their system efficiency (the amount of light that actually reaches the target area after all losses are accounted for). Most values for LED system efficiency fall above 50 lumens/watt.

Fluorescent and CFL lights are very efficient compared to incandescent lights (50-100 lumens/watt source efficiency). They lose out to LEDs principally because their system efficiency is much lower (&lt;30 lumens/watt) due to all of the losses associated with omnidirectional light output and the need to redirect it to a desired area.

WINNER: LED

Heat Emissions LEDs emit very little forward heat. The only real potential downside to this is when LEDs are used for outdoor lighting in winter conditions. Snow falling on traditional lights like HID will melt when it comes into contact with the light. This is usually overcome with LEDs by covering the light with a visor or facing the light downward towards the ground.

Fluorescent lights emit heat that is absorbed by the ballast and/or lost to the environment. Roughly 15% of the emissions are lost due to energy dissipation and heat losses. In some circumstances heat emissions could be beneficial, however, it is generally a bad thing to emit heat as it represents an energy inefficiency. The ultimate purpose of the device is to emit light, not heat.

WINNER: LED

Life Span LEDs last longer than any light source commercially available on the market. Lifespans are variable but typical values range from 25,000 hours to 200,000 hours or more before a lamp or fixture requires replacement.

Fluorescent lights have good lifespan relative to some bulbs but not compared to LED. Typical lifespan values range from 7,000 hours to 15,000 hours before a bulb requires replacement. Note: sometimes fluorescent lights need to be changed out before the end of their useful life to preempt serious degradation effects like flicker or changing light color (turning pink).

WINNER: LED

Lifetime Cost LED lighting has relatively high initial costs and low lifetime costs. The technology pays the investor back over time (the payback period). The major payback comes primarily from reduced maintenance costs over time (dependent on labor costs) and secondarily from energy efficiency improvements (dependent on electricity costs).

Fluorescent lights are relatively cheap to purchase but relatively expensive to maintain. Fluorescent bulbs will likely need to be purchased several times and the associated labor costs will need to be paid in order to attain the equivalent lifespan of a single LED light.

WINNER: LED

Maintenance Costs LED has virtually zero maintenance costs and the frequency with which bulbs have to be changed out is by far the best on the market.

Fluorescent bulbs require regular relamping and ballast replacement in addition to the labor cost to monitor and replace aging or expired components .

WINNER: LED

Upfront Costs LED has virtually zero maintenance costs and the frequency with which bulbs have to be changed out is by far the best on the market.

Fluorescent bulbs require regular relamping and ballast replacement in addition to the labor cost to monitor and replace aging or expired components.

WINNER: Fluorescent

Shock Resistance LEDs are solid state lights (SSLs) that are difficult to damage with physical shocks.

Fluorescent bulbs are particularly fragile - especially T5, T8, and T12 tubes. Perhaps more importantly, broken fluorescent bulbs require special handling and disposal due to hazardous materials like mercury inside the lights.

WINNER: LED

Size LEDs can be extremely small (less than 2mm in some cases) and they can be scaled to a much larger size. All in all this makes the applications in which LEDs can be used extremely diverse.

Compact fluorescent lights (CFLs) are designed to be small (such that they can replace an incandescent household light). Even so, they typically aren’t produced below roughly a centimeter in width. Standard fluorescent tubes are bulky and fragile at the same time. Neither compare to the small size and robust build of a solid state light like LED.

WINNER: LED

Cold Tolerance LEDs - Minus 40 Degrees Celsius (and they will turn on instantaneously).

Fluorescent lights with regular magnetic ballasts (such as the T12 tube) are not generally recommended for temperatures below 50-60 Degrees Fahrenheit. For colder weather choose a fluorescent light with an electronic ballast such as a T8 tube.

WINNER: LED

Heat Tolerance LEDs - 100 Degrees Celsius. LEDs are fine for all normal operating temperatures both indoors and outdoors. They do, however, show degraded performance at significantly high temperatures and they require significant heat sinking, especially when in proximity to other sensitive components.

We couldn’t find any objective data on fluorescent bulb performance in high temperature situations. If you have any information please contact us!

WINNER: LED

Warm Up Time LEDs have virtually no warm-up time. They reach maximum brightness near instantaneously.

Fluorescent lights (particularly the older technology) require a noticeable warm up time that varies depending on the light.

WINNER: LED

Warranty LEDs - Often 5-10 years

Fluorescent lights - typically 1-2 years

WINNER: LED

Winter Weather Conditions LEDs produce significantly less heat than conventional gas discharge lights. This is typically a positive, however, for the unique case of application with traffic lights, there is a small potential that snow can accumulate on the bulbs. In reality, however, this is generally not an issue due to the use of visors and/or proper orientation of the light within a fixture that shields it from the elements.

Fluorescent bulbs are not generally recommended for outdoor lighting. CFLs will work but as the temperature drops the light quality suffers significantly. This is noticeable slightly below the freezing level and dramatic below about 5 degrees Fahrenheit.

WINNER: LED

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