Can incandescent bulbs be substituted by LEDs?


LEDs: quality and effects

1. Definition

"Light Emitting Diodes (LEDs) produce visible light using the electroluminescence of a compound semiconductor crystalline material. This process is potentially more energy efficient than either incandescence or fluorescence. When connected to a power source, the flow of current triggers a quantum mechanical process inside the diode, which produces light in specific colors (usually red, green or blue). White light is created by combining the light from these colored LEDs or by coating a blue LED with yellow phosphor (Department of Energy 2008).

Organic LEDs (OLEDs) produce visible light when an electrical charge is applied to extremely thin organic materials layered between two electrodes. The technology is still in the early stages of development, but has the potential to efficiently produce visually appealing white lighting in a thin, flexible form that could compete directly with fluorescent and conventional LED lighting." (U.S. Department of Energy, Critical Materials Strategy, December 2010, p. 21)

Do LEDs pose a photobiological hazard? Given the limited spectral distribution of LEDs, there are no concerns about UV and IR radiation. What remains is the potential of photochemical damage to the retina from blue light.

2. Health effects of lighting systems using LEDs

See Health effects

3. Reliability of LEDs

Manufacturers of LEDs announce lifetimes of white LEDs up to 50 000 hours measured under laboratory conditions (junction temperature maintained at 25 C and fixed current); but in a current lighting system, measurements show that, in extreme cases, they may lose more than 70% of their brightness after 1000 hours of operation. The lifetime of the LED depends on the temperature of the junction and the electric current intensity, without forgetting the quality of production and integration. At present, the definition of the lifetime of a LED and the measuring method are not standardized. (ANSES_Report 2010, p. 40)

The junction temperature

The heat is "enemy No. 1" of LEDs, more specifically of white LEDs. LED operation at too high a temperature (and therefore high junction temperature of the semiconductor) has a dramatic effect on efficiency but also on other characteristics and performance of LEDs such as the flux, the spectrum (and thus the color), the polarization voltage, and the life. To take advantage of the interesting properties of LED (flux, efficiency, durability, quality of light emitted), integrators must take into account the heat generated by the LED and qualities of this component to evacuate the heat. However, even with excellent thermal management of LEDs in the final application, the resulting temperature at the junction of the semiconductor is far from the 25 C, reference temperature of most manufacturers. (ANSES_Report 2010, p. 207)

LED lamp life expectancy depends on fixture type and usage scenario

4 September 2014 in LEDsMagazine: LED lamp life expectancy depends on fixture type and usage scenario. "Consider for a moment the ecological predecessor of the LED lamp the CFL. Has it become common knowledge among consumers that CFLs will not perform as claimed in some fixture applications? (...) In fact, LED lamps can and do fail even sooner and of course at higher fiscal cost. (...) The general public needs a range of life expectancy as the lamp is used by the consumer. We have to move beyond the never and always paradigm, or we risk having LED technology disappoint the buying public more than CFLs have."

ÖKO-TEST, 23 March 2012

  • 11 LEDs with a E27 screw thread were tested. You have to pay between 30 to about 80 euros to have a dimmable model. Comparison was made with an incandescent light bulb of 60W (about the same brightness).
  • LEDs are very expensive, up to 70 times the price of an incandescent bulb. But projected to the years of use, it pays off. A certain LED lamp is said to save the purchase price of EUR 44.95 after a good three years. But on the other side, the energy required for the production of a LED is much larger than for an incandescent lamp. And the LED bulb should not simply end in the household waste but must be disposed of in a municipal collection point for electrical equipment. Therefore, the most economical LED is given in the test the maximum label "good" concerning energy efficiency.
  • The complex electronics gives rise to electrosmog. In all LEDs increased low-frequency electric fields were measured, resulting from the mains frequency. Two LEDs showed fields that were ten times as large as allowed for computers monitors! Higher-frequency fields, however were, contrary to CFLs, not a problem with the tested LEDs. Conspicuous harmonics and steeply rising pulse structures create in all LED lamps in the test additional unpleasant electrosmog that can affect, among other things, the nervous and endocrine systems.
  • The announced lumen and the number of hours the lamp will be shine, is sometimes grossly exaggerated.
  • 7 LEDs didn't reach the brightness of a 60W incandescent lamp.
  • Concerning the light colour, most LEDS have problems to illuminate a room so that it looks natural. On the other hand, when it comes to color reproduction, LEDs can overtake CFLs. "Incandescent and halogen lamps remain the optimum", according to Wolfgang Maes, building biologist.
  • One lamp exceeded in the range 50-950 kHz the standard limit of radio interference. With this lamp in the room, there may be some problems with the radio alarm or motion detectors can go haywire because the radio link is disrupted.

Conclusion: The quality of the current supply of LED lamps is unsatisfactory.

4. LEDs can damage the paintings of great masters!

The Dutch newspaper De Volkskrant, February 15, 2011: It was found that over a period of more than one hundred years many original yellow colors on Vincent van Gogh's paintings slowly became brown. An international team of scientists suspected that the discoloration could be caused by the chrome that the painter used in his paint. On January 4, 2013, De Volkskrant reported the reason of this discoloration, referring to the doctorate of Letizia Monico at the universities of Antwerp and Perugia. 'Our research shows that middle chrome yellow, which is a yellow hue with warm glow and is most often used, is chemically fairly stable.'

Van Gogh also uses the lighter lemon yellow and even pale primrose yellow. 'They react very intensely to light beams. After only a few days they colour during our tests to brown and olive green. These unstable forms of chrome yellow paint we found among others in some very famous paintings, such as the Portrait of Gauguin and Vase with sunflowers.'

Also other painters used both the stable and unstable forms of chrome yellow paint such as Paul Cézanne and according to the Belgian newspaper De Standaard of 4 January 2013, also Rik Wouters.

Because the lemon and primrose yellow extra sensitive to blue and green, it is risky to illuminate those artworks with LEDs because they emit a high proportion of blue light. LEDs can damage the paintings of great masters!

5. LEDs use less REEs than CFLs but REEs remain crucial

General lighting service (GLS) sources are defined as white-light sources used to illuminate spaces. (Leslie Lyons, Part 1)

White light LED devices are generally based on one of three approaches for producing a distribution of visible wavelengths that are perceived as "white light". These are:

  1. phosphor-conversion LEDs (pcLEDs);
  2. discrete color-mixing; or
  3. a hybrid method, as shown in the figure below (DOE, 2012b).

Source: U.S. Department of Energy, Life-Cycle Assessment of Energy and Environmental Impacts of LED Lighting Products, Part 2: LED Manufacturing and Performance, June 2012, p. 19

  • Phosphor-conversion LEDs create white light by blending a portion of the blue light emitted directly from the chip with light emission down-converted by a phosphor from the blue part of the spectrum to other colors.
  • Discrete color-mixing, on the other hand, starts with discrete colored sources and uses color mixing optics to blend together the light output to create white light emission.
  • The hybrid method uses a combination of pcLEDs and discrete-colored LEDs to create the desired light output. (Same source, p. 19)

The majority of white light LEDs in production today are phosphor converting LEDs based on galliumnitride, emitting blue light between 450-470 nm (DOE, 2011). This blue light excites a yellow phosphor, usually made of Ce3+:YAG crystals that have been converted into a powder. As the LED chip emits blue light, some is emitted directly through the phosphor and some is converted by the phosphor to a broad spectrum centered around 580 nm (yellow) by the Ce3+:YAG. This yellow light stimulates the red and green receptors in the human eye, resulting in a mix that gives the appearance of white light. (Same source, p. 19)

Summary of LED Colors and Common Chemistries (Same source, p. 17)

Color Wavelenght Materials
Infra_Red 850-940 nm Gallium arsenide, Aluminum gallium arsenide
Red 630-660 nm Aluminum gallium arsenide, Gallium arsenide phosphide, Gallium phosphide
Amber 605-620 nm Gallium arsenide phosphide, Aluminum gallium indium phosphide
Yellow 585-595 nm Aluminum gallium phosphide, Gallium arsenide phosphide, Gallium phosphide
Green 550-570 nm Aluminum gallium phosphide, Gallium nitride
Blue 430-505 nm Indium gallium nitride, Gallium nitride, Silicon carbide, Sapphire, Zinc selenide
Ultraviolet 370-400 nm Indium gallium nitride, Aluminum gallium nitride

Toxicity of used materials: Particularly those workers involved in the manufacturing process and destruction of LEDs could be exposed.

  • indium phosphide (InP): Indium itself does not seem te be a problem of of toxicity, but its compounds, often used in the manufacture of LEDs, can present some danger. Thus, the toxicity of indium phosphide (InP) is estimated at 3 on a scale of 4 according to the American standard NFPA 704 [NFPA 2007]: "product may after a short exposure, cause temporary serious or moderate residual lesions." Indium phosphide is carcinogenic. A study published in 2002 [Tanaka et al., 2002] evaluated the pulmonary toxicity of indium phosphide in hamsters. (ANSES_Report 2010, p. 127)
  • gallium arsenide (GaAs): The toxicological properties of gallium arsenide have not been thoroughly investigated. On one hand, due to its arsenic content, it is considered highly toxic and carcinogenic. On the other hand, the crystal is stable enough that ingested pieces may be passed with negligible absorption by the body. California lists gallium arsenide as a carcinogen. (
  • aluminium gallium arsenide (AlxGa1-xAs): Little information exists about adverse health impacts that workers who are exposed to these particles face, but increased use of AGA has raised concern regarding occupational exposure because it has been scientifically proven to be toxic to animals (;
  • Gallium arsenide phosphide (GaAs1-xPx): (
  • Gallium phosphide (GaP): Chemical, physical and toxicological properties of gallium phosphide have not been thoroughly investigated and recorded. More information.
  • Aluminum gallium indium phosphide (AlGaInP): The toxicology of AlInGaP has not been fully investigated. The dust is an irritant to skin, eyes and lungs. (
  • Aluminum gallium phosphide (AlGaP): No relevant information found
  • Gallium nitride (GaN): GaN dust is an irritant to skin, eyes and lungs. It has been found non-toxic. (Source)
  • Indium gallium nitride (InGaN): The toxicology of InGaN has not been fully investigated. The dust is an irritant to skin, eyes and lungs. (Source)
  • Silicon carbide (SiC): Hazardous in case of skin contact (irritant), of eye contact (irritant), of ingestion, of inhalation
  • Zinc selenide (ZnSe): Toxic by inhalation. Dust may be irritating to eyes and respiratory system.
  • Aluminum gallium nitride (AlGaN): The toxicology of AlGaN has not been fully investigated. The AlGaN dust is an irritant to skin, eyes and lungs. (Source)

Phosphors accounted for 7% of all REE usage by volume and 32% of the total value in 2008 (Kingsnorth 2010). The exact composition of phosphors, including REE variety and weight percentages, differs by manufacturer and is considered proprietary information. Emerging lighting technologies have dramatically lower REE content than fluorescent lamps. (DOE_2010, p. 21-22)

  • White LED designs eliminate the need for lanthanum and terbium phosphors, but may still use cerium and europium phosphors to convert blue LEDs to useful white light. Gallium and indium are used in the formation of the LED compound semiconductor material. Some manufacturers add neodymium as a glass component to shift the color of certain products to more closely resemble natural light. However, in 2010 this use represented a very small percentage of overall neodymium use (General Electric 2010).
  • OLEDs can be free of all lanthanides, but bulb manufacturers may still use other key materials such as indium.

In the short and medium terms, the demand for LFL and CFL fluorescent lamps using REEs in their phosphor formulations is expected to increase. (...) In the long term, LED and OLED technologies will likely capture a significant share of the lighting market as their cost and performance make them increasingly competitive with fluorescent technologies. This change could mitigate the demand increase for REE phosphors.(p. 22-23) Light emitting diodes (LED) use little or no REEs and could replace fluorescent light bulbs. LEDs for room lighting are not expected to be cost competitive until the medium term. (DOE_2010, p. 120)

Because of the new quotas introduced by China, the availability of rare-earth elements causes some concern. (

Gallium demand is growing in several applications including light-emitting diodes (LEDs) used for liquid crystal displays in televisions and notebook computers and solar cells. In addition, its material intensity in solar cells has been declining thanks to efficiency improvements. Electronic components have represented about 98% of U.S. gallium consumption since 2003. In 2009, about 67% of the gallium consumed was used in integrated circuits (ICs). Optoelectronic devices, which include laser diodes, LEDs, photodetectors, and solar cells, represented 31% of gallium demand. The remaining 2% was used in research and development, specialty alloys, and other applications. The global economic downturn hurt LED markets, although emerging LED market segments, such as for LCDs in televisions and notebook computers, still showed growth. At the same time, record-making solar cell efficiencies are reducing the need for gallium, among other materials, in making thin film solar cells (USGS 2010c).

The United States represents about 25% of the global annual consumption of gallium. Since 1982, the United States has been dependent chiefly on imports for meeting its annual gallium demand. (p. 40)

Indium base material for the majority of current LEDs is a rare element: 61st in abundance on the Earth's crust (0.24 ppm (parties par million) by weight). Indium is not exploited as the main product (there are no mines indium). Indium is a subordinate product of zinc, but also of tin. Indeed, it is ranked second on the list of the rarest strategic materials. Although a LED junction uses a tiny amount of this element, it is impossible to recycle it after use. Today the world's reserves amounted to 5600 tons and are therefore sufficient for the years to come, but they are not inexhaustible. Today, more than 75% of indium is used by the flat screen industry for the manufacture of transparent electrodes in ITO (Indium Tin Oxide). According to analysts, the most likely scenario is that the industry will face a situation of periodic short-term "crisis" (2-3 years). (ANSES_Report 2010, p. 215)

LEDs: Higher toxicity and resource depletion

  • New research shows CFLs and LED light bulbs have higher toxicity and resource depletion than incandescent bulbs (January 16th, 2013)
  • Fact Sheet: Mineral Products and Metals that make LED Light Bulbs
  • Seong-Rin Lim, e.a., Potential Environmental Impacts of Light-Emitting Diodes (LEDs): Metallic Resources, Toxicity, and Hazardous Waste Classification, published in Environmental Science & Technology, 2011, 45(1), pp 320-327, December 7, 2010.

    The environmental burden associated with resource depletion potentials derives primarily from gold and silver, whereas the burden from toxicity potentials is associated primarily with arsenic, copper, nickel, lead, iron, and silver.

  • SCHEER, Preliminary Opinion on Potential risks to human health of Light Emitting Diodes (LEDs), July 2017. Hazardous waste due to the materials used for producing Light-Emitting Diodes (LEDs). A South Korean/U.S. investigation on the toxic potential of LEDs, CFLs and incandescent lamps, found that in comparing the bulbs on an equivalent quantity basis with respect to the expected lifetimes of the bulbs, the CFLs and LEDs have 3-26 and 2-3 times higher toxicity potential impacts than the incandescent bulb, respectively (Lim et al., 2011).
    • Arsenic is present as gallium arsenide is found in light emitting diodes (LEDs). The element is a human carcinogen and exposure to arsenic can result in various skin diseases and can decrease nerve conduction velocity.
    • Lead is a potent neurotoxin, and short-term exposure to high concentrations of lead can cause vomiting, diarrhoea, convulsions and damage to the kidney and reproductive system. It can also cause anaemia, increased blood pressure, and induce miscarriage for pregnant women. Children are considered to be particularly vulnerable to exposure to lead, for it can damage nervous connections and cause brain disorders.
    • TBBA (tetrabromobisphenol-A), PBB (polybrominated biphenyls) and PBDE (polybrominated diphenyl ethers) could be encountered as fire retardants for plastics (thermoplastic components, cable insulation). TBBA is presently the most widely used flame retardant in printed wiring boards and covers for components - brominated flame retardants (BFRs). The combustion of these halogenated compounds releases toxic emissions including dioxins which can cause reproductive and developmental problems, damage the immune system, interfere with hormones and also cause cancer.
    • Polyvinyl chloride (PVC) is mainly found in the plastic components of electrical and electronic equipment. When burned, PVC releases dioxins, furans and phthalates, some of which are known reproductive toxicants and carcinogens (Hazardous substances in e-wastes., 2009).
    • Phthalates used as softeners to PVC can easily leach into the environment. Epidemiological data has suggested an association between indoor exposure to phtalates and asthmatic and allergic reactions in children (Bornehag et al., 2010)

The new LED light

For the future a new form of LED light is introduced. The ideal is a tunable white light produced by a combination of red, green and blue LEDs. During the day, different hues can be amplified or suppressed so that the natural light of the sun is mimiced. (Jeff Hecht, Better than sunshine: See life in an improved light, New Scientist, 6 July 2012.) Article


After having accomplished the ban on incandescent bulbs, and leaving the CFL technology unsatisfactory for the consumers, the lamp manufacturers are now focussing strongly on the lucrative LED technology. The consumers have to pay a huge price for a dangerous and disagreeable product. The rights of the consumer are denied. They don't understand why the EU supports this course of events. Even managers are not happy with each decision: Products shall not be banned if no suitable and affordable good quality replacement products are available. (Lars Stühlen, ELC)

It is very important to stress that LEDs produce a different type of light in comparison with incandescent light. So, they cannot be a substitute product! A ban of incandescent light bulbs has led to a very reduced choice of light products. This is the more incomprehensible because the light belongs to the necessary elements influencing our mental and physical health (together with food, water and air). Our sight is more valuable than a possible saving of electricity consumption. And our environment has much less to endure from incandescent light bulbs than from CFLs or LEDs. This is proven by Greenpeace in Berlin in 2007. By destroying 10,000 incandescent light bulbs, they showed that the clearout of the broken lamps was no problem at all! Imagine what would happen when 10,000 CFLs or LEDs were destroyed! A whole quarter should be evacuated! Let us eliminate the burden of toxicity and resource depletion potentials needed to produce the 'energy saving' light bulbs.


Last updated on 15 August 2017