While compact fluorescent lamps have replaced incandescent lamps in just a few years, LED lamps are now widely available in the home lighting market. Used in homes as well as in displays, LED lamps have many advantages but must be used with certain precautions that we detail.
According to a report by IWM, lighting currently accounts for 12% of electrical consumption in a home (excluding heating and hot water).
Energy consuming and inefficient, incandescent lamps have been, since 2009, gradually withdrawn from the French market to be finally banned in September 2012 by the European Union. They were mainly replaced by compact fluorescent lamps (or low-energy lamps) which were propelled onto the market thanks to massive communication, the virtual absence of competing technologies and significant advantages: they last 8 to 10 times longer and consume 4 to 5 times less energy for equivalent lighting.
As a result, in just a few years, compact fluorescent lamps have become the standard in most homes and businesses. And yet, they are not without their critics and defects:
some lamps have a limited life span that does not correspond to the advertisements;
some lamps have a long start-up time that can exceed one minute;
they emit ultraviolet (UV) radiation that can be harmful to certain sensitive populations;
They all contain mercury, a dangerous metal that must be properly recycled.
Presented as durable, low-energy lamps are in reality only a temporary palliative before the democratization of much more efficient and ecological lamps: LED lamps that have appeared on the shelves of retailers.
LED lamps: definition
A light-emitting diode (LED) is an electronic component allowing the transformation of electricity into light. Its main applications, in order of market importance, are mobile electronics, displays, the automotive sector, lighting and signage.
For lighting, we use lamps consisting of several high-power LEDs joined together, since at the unit their luminous flux (measured in lumen or lm) is still too low.
There are also LED modules, which are assemblies of one or more LEDs mounted on a printed circuit board, with or without light control devices. LED modules usually require special fixtures, but some can also be implemented in existing fixtures. Like LED lamps, they are replaceable.
It was not until 2000 that high-power LEDs and white LEDs appeared, thanks to major R&D efforts, with the ambition of competing with existing technologies for home, workplace and outdoor lighting.
The advantages of LED lamps
LED technology continues to progress: LED performance doubles every 2 years and prices drop by 20% every year.
The lifespan of LED lamps is far superior to that of other technologies: up to 100,000 hours (in the laboratory), 40,000 hours on the market (i.e. several decades of use) compared to 1,000 hours for incandescent lamps, 2,000 hours for halogen lamps and 10,000 hours for CFLs. Thus, the purchase and replacement of LED lamps are less frequent, which improves the return on investment.
Good energy efficiency with significant potential for improvement
While an insulated LED has a very good energy efficiency (about 150 lm/W and up to 220 lm/W for the most efficient ones), a LED lamp offers an efficiency between 40 and 80 lumens per watt. This decrease in efficiency is mainly due to the heat produced by the diodes attached to the lamp.
Thus, LED lamps currently on the market have generally a much higher energy efficiency than conventional lamps: 70 lumen / W for compact fluorescent lamps and only 16 lumen / W for incandescent lamps.
Fortunately, the majority of lamps intended for domestic lighting today offer a satisfactory quality of lighting: an LED lamp of more than 800 lumens (equivalent to an incandescent lamp of 60 W) consumes between 9 and 12 watts only, a LED of 400 lumens consumes about 6 watts.
In addition, technological developments should improve the efficiency of LED lamps for the general public by bringing it around 100 lm / W. The “super bright” LEDs can already, in the laboratory, reach an energy efficiency of up to 300 lm / W! This means that in the future we will be able to have lamps that consume less than 4 watts and that light up like a 75-watt incandescent lamp.
Instant maximum light
LED bulbs reach maximum brightness as soon as they are switched on. In fact, LED sources allow for frequent on/off cycles. They instantly emit the desired luminous flux without ramping up, which can be advantageous for specific applications such as high-traffic areas.
The compactness of LEDs makes them very interesting for replacing recessed sources in false ceilings such as halogen spotlights or downlights.
LED modules, which can be installed directly in a luminaire and can incorporate control electronics, facilitate the implementation of lighting management solutions such as presence detection or daylight-dependent dimming.
LEDs operate at very low voltages and even at low temperatures, which can be an advantage for electrical safety in the building.
With a temperature rise of only 32°C, LEDs do not heat up as much as incandescent lamps (150°C) and compact fluorescent lamps (70°C).
They are insensitive to shocks, which makes them more robust than other light sources. Colored LEDs can be used for light shows without the use of filters.
Finally, LEDs do not contain mercury and are largely recyclable as non-hazardous waste (unlike CFLs).
Disadvantages and ways to improve LEDs
The manufacturing process of LEDs is relatively energy intensive. However, the overall energy balance (including the manufacturing and use) of the two technologies (LED and CFL) is comparable.
With their democratization, the prices of LEDs have been divided by 2 or 3 in just 3 years. In 2017, it is necessary to count between 100 and 250 pesos for a lamp that illuminates as much as an incandescent lamp of 60 W and about 350 pesos for the equivalent of 75 W. Of course, with their massive market deployment (over $30 billion in 2017 according to LED Inside), prices have dropped rapidly, much to the delight of consumers.
LED lamps are still ill-suited for high-powered lighting, especially in the street lighting market due to the overheating that can result from using many LEDs side by side. And this even if, individually, a LED lamp does not heat up much.
An environmental balance to improve
In addition to energy consumption during operation, LED lamps generate environmental impacts during their manufacture and at the end of their life. The International Energy Agency has compiled several life cycle analyses of lighting solutions that compare the environmental performance of incandescent lamps, CFLs and LEDs.
The environmental impact of a light source is mainly determined by its efficiency to produce light and its lifetime. Thus, the environmental impact of CFLs and LEDs is still much lower than that of incandescent lamps (up to 75% lower).
Future progress on the luminous efficacy and lifetime of LEDs should enable them, in the long term, to have the best environmental record of all lamps, with an 85% reduction in environmental impact compared to incandescent lamps. This record can also be improved by progress in manufacturing and recycling.
Today, some of the materials used to manufacture LEDs, particularly indium and gallium, are considered critical because resources are running out. Moreover, these materials cannot be recycled. The challenge is to reduce the amount of these materials in the LED and to successfully recycle them. LED manufacturers can take action by planning the disassembly and recycling of the lamp from the design stage.
LEDs contribute more to light pollution
While the number of light points in the world continues to increase dramatically, contributing to light pollution, the democratization of LED lamps further accentuates this trend. However, the blue component of “white” LEDs diffuses more in the atmosphere and “causes halos 10x higher than those of a sodium lighting with equal light power. They are also more dazzling, still has equal light power: this tends to close more the retina and therefore limit the entry of light: it illuminates as much, but ultimately we see less well, “said the association of astronomers Avex.
Are LEDs really dangerous for health?
Some scientists warned consumers about the health risks associated with the high proportion of blue light emitted by LED lighting cold white and blue: “exposure, even very low, to light rich in blue in the evening or at night, disrupts the biological rhythms and therefore sleep. Some scientists emphasizes that screens including computers, smartphones and tablets are important sources of blue-rich light and children and adolescents, whose eyes do not fully filter blue light, are a particularly sensitive population.” It is therefore advisable to limit children’s exposure to blue-rich light from LED screens (cell phones, tablets, computers, …) before bedtime and at night.
It is now possible to set the lighting of the latest screens and smartphones to significantly reduce blue light.
In addition, some scientists “recalls the importance of preferring domestic lighting type “warm white” (color temperature below 3000K).
However, scientists from Europe are reassuring: “only certain high-power LED sources reserved for professional applications (outdoor lighting of great height for example) are concerned.
They are not available for sale for normal lighting uses inside buildings, and safety measures are taken for their use.
In addition, “all manufacturers of LED lights and bulbs must verify that their products do not emit too much blue light, for this they use methods defined in the European standards NF EN 62471, and IEC/TR 62778 at the global level. The CE mark affixed to these products commits the manufacturer to compliance with the regulations”.
Finally, it is recommended to stay more than 20 cm from a LED light source. Indeed, according to a study by the University of Madrid, blue LED lamps could irreversibly damage the cells of the eye. However, the conditions that led to these results are unlikely to be met: being exposed to blue LED lamps with a brightness equivalent to an incandescent lamp of 100 W, at a distance of 20 cm and for 12 hours …
What about low frequency electromagnetic fields?
If the low frequency electromagnetic radiation (50kHz) exceeds 100 V/m at the very contact of the lamp, it decreases strongly at 20 cm (less than 10 V/m) and is drowned in the background noise of the electromagnetic field at 50 cm. The WHO recommends not exceeding 87 V/m.
In the end, if some obvious precautions are taken (do not stick to the lamp), there is no risk for individuals who want to equip their home. Only the blue light must be taken seriously.
The LEDs impose themselves against compact fluorescent lamps
LED lamps are increasingly efficient and widespread among distributors and are now the majority in the lighting market with a penetration of over 52%.
The major manufacturers of LEDs for lighting are from the semiconductor industry and are concentrated in Japan, the U.S. and Korea.
Efficient and energy-saving lamps for everyone’s lighting needs
The “Global Efficient Lighting” forum held in Beijing, China, on November 10-11, 2014, stated that if all light sources switched to LED technology, the world’s power consumption for lighting would halve, while without ambitious targets, by 2030 the power consumption to produce light is expected to increase by one-third!
Buying a LED to test is adopting it: the benefit for the quality of lighting is obvious with a real gain in energy efficiency. Apart from a few precautions, LEDs undoubtedly signal the end of the life of compact fluorescent lamps, which have only just become popular in homes.
Moreover, the popularity and efficiency of LED lamps have been rewarded by the award of the 2014 Nobel Prize in Physics to the Japanese and American inventors of blue and white LEDs, namely: Isamu Akasaki, Hiroshi Amano and Shuji Nakamura. Their work has enabled these diodes to be used massively in industry.
The Nobel organization concludes that their discovery has made it possible: “to increase the quality of life of more than 1.5 billion people in the world who do not have access to electricity networks: thanks to its low power consumption, LEDs can be powered by local and inexpensive solar energy.
Today, 80% of new lighting projects are equipped with LEDs.