WHEN PRESENTED WITH TOO MANY CHOICES STUDIES SHOW THAT WE TEND TO SELECT THE CHEAPEST OPTION.
When purchasing LED lamps or fixtures, it can be tempting to go for the option with the lowest cost. However, the LED lighting market is flooded with all types of products, and not all of them come from reliable manufacturers. When low-quality products are used, the negative consequences outweigh the upfront cost savings, and they end up being the most expensive option in the long run.
The two most common issues with low-grade LED products are poor lighting quality and a short service life, and sometimes both issues are present at once with the same product.
How to Avoid Poor Lighting Quality
The quality of lighting products is measured with the Colour Rendering Index (CRI), which indicates how their output compares to that of a natural light source such as the sun. The highest CRI value is 100 and it means the light source offers a high-quality output, faithfully representing the colours of objects and surfaces. As the CRI value is reduced colour perception is distorted, and the metric can reach negative values for extremely poor lighting quality.
Reputable lighting manufacturers label the CRI in their products, giving the client a clear description of what lighting quality to expect. For example, an LED bulb with a CRI of 80 tends to have a lower price than one with a CRI of 98, but the lighting quality is diminished proportionally.
However, some LED manufacturers focus on energy efficiency at the expense of everything else, even colour rendition. They advertise their products based only on energy savings, and the CRI may be omitted or displayed in small text that is easy to overlook. When customers purchase these LED bulbs, they are often disappointed by the poor lighting quality and go back to incandescent or halogen lighting, which have a perfect CRI of 100 despite their inefficiency.
Is the Rated Service Life Real?
LED products last significantly longer than older lamp types. For example, residential LED bulbs typically last for 25,000 hours, while commercial and industrial products typically exceed 50,000 hours. Established lighting manufacturers carry out laboratory tests to ensure that the reported service life is realistic, typically based on the LM-80 and TM-21 standards from IESNA, which provide a detailed procedure to calculate the service life of LED products.
Any manufacturer can print a rated service life on a product label, however, and in some cases the value is completely omitted. Some of the cheapest LED lamps have not been tested properly and may fail in a matter of months or even weeks. A lamp replacement is necessary in these cases, negating any savings obtained from the purchase of a cheap product.
Upgrading to LED lighting is an investment, with an upfront cost and long-term benefits that outweigh the expenses. However, there are low quality products that are unable to deliver what they promise: they have a very low price, but their lighting output is deficient and they tend to fail prematurely. To make sure you obtain a return on your investment, purchase products that have been properly tested and come from reliable manufacturers.
High-intensity discharge (HID) lighting is commonly used in outdoor and industrial applications due to its potent output per bulb.
Unfortunately, HID lighting comes with a high cost of ownership:
- Installation costs are high because these fixtures are normally located high above the ground, hanging from industrial rooftops or mounted on poles.
- The service life of HID fixtures is decent, ranging from 10,000 to 24,000 hours depending on the specific type of bulb, but frequent replacements are required because these lamps work for long hours and are susceptible to switching and thermal stress.
- The power consumption of HID lighting is high: they are more efficient than incandescent lamps, but less efficient than fluorescent tubes, and significantly less efficient than LED fixtures.
The three most common subtypes of HID lamps are metal halide (MH), high-pressure sodium (HPS) and mercury vapor. There is also a type called low-pressure sodium (LPS), which offers a very high luminous efficacy but a very poor lighting quality, which limits its applications.
LED lighting offers significant advantages over HID lighting, in great part due to its energy efficiency and long service life. When the upgrade is carried out, energy savings can range from 40 to 80 percent, which lamp replacements becoming 5 to 10 times less frequent.
Service Life Comparison Between HID and LED Lighting Products
To get an idea of how LED lighting provides maintenance savings when replacing HID fixtures, consider the typical service life of the three main types of HID lamps:
- Metal halide: 9,000 to 12,000 hours
- Mercury vapor: 18,000 to 24,000 hours
- High-pressure sodium: 18,000 to 24,000 hours
Metal halide lamps are commonly used for indoor industrial lighting, since they provide the best lighting quality of all three types despite their reduced service life. The other two types are more common in outdoor applications, where the colour performance of lighting is less critical.
However, LED bulbs typically last for 50,000 hours, while integrated LED fixtures can reach up to 100,000 hours. If you were to upgrade the lighting from MH to LED fixtures in an industrial warehouse, for example, lamp replacements would become 10 times less frequent. When you consider that these lamps are high above the ground, and qualified personnel must climb on a ladder or hoist to replace them, the labour savings associated with avoiding ten replacements are significant.
LED Lighting is Much Better Suited for Lighting Automation
Each time an HID lamp is activated, it establishes an electric arc to ignite a gas and produce lighting, and this process can wear down the lamp very quickly if it is frequently switched on and off. Hence, HID lighting is better suited for applications where the lights will operate for long periods of time. If lighting controls are deployed to activate and deactivate lamps as needed, their service life is cut short and replacement costs offset any energy savings achieved.
LED lighting does not suffer from this limitation, as the lamps are much more tolerant to frequent switching: they are solid-state devices that don’t rely on gas ignition. Automation can enhance the savings achieved when upgrading from HID to LED lighting. For instance, if you reduce the lighting power by 50% and the time of use by 20%, your lighting costs are being reduced to only 40% of their previous value.
LED lighting also makes facilities safer, since it can be reignited instantly after a service interruption. This is not possible with HID lamps, which typically have a restrike time of several minutes, leaving facilities and outdoor locations in the dark during their cool down period.
Office buildings normally use parabolic fixtures with T8 fluorescent tubes, which offer a decent performance but are outclassed by LED lighting in terms of both efficiency and service life.
When upgrading linear fluorescent lighting in office spaces, there are two main options:
- Keeping the existing fixtures and using T8-equivalent LED tubes, which are designed for the same lamp holders used by fluorescent tubes.
- Using integral LED panels, which are designed to replace the whole fluorescent fixture, not only the tubes.
There are significant energy savings to achieve with both upgrade options, and neither can be considered better than the other; the best option is determined by project conditions.
LED Replacement Tubes
There are a broad selection of LED products designed to replace T8 tubes directly, and the main advantages they offer are low cost and fast installation. Some of these LED tubes are compatible with T8 ballasts and can be replaced directly while others are designed for the main power supply and require the ballast to be disconnected and bypassed.
The former replacement tubes do not save as much power as the tubes that are designed to run with a bypassed ballast. Bypassing the ballast enables the LED to consume the least amount of power possible leading to greater savings.
LED replacements for 36-watt T8 lamps typically consume between 15 and 22 watts, which means energy savings between 30 and 50 percent can be expected. If the ballast is bypassed the unit will use an additional 10 watts less as this 10 watts is normally consumed by the ballast itself.
LED tubes offer a service life of 50,000 hours on average, which is 2.5 times longer than the 20,000 hours offered by T8 fluorescent lamps. Other than reducing energy consumption, LED tubes also provide savings by avoiding frequent lamp replacements.
LED replacement tubes are an excellent choice in existing facilities, since they allow a quick and affordable upgrade with minimal disruption of work activities.
Integral LED Fixtures
This approach yields an efficiency that is 10 to 15 percent higher than that achieved when only the tubes are upgraded, but the installation also has a higher cost in terms of both materials and labour. This type of upgrade is more cost-effective when a major renovation is carried out, or in new projects where it allows ballasts and tubes to be avoided completely. Although a full fixture upgrade is also financially attractive in existing projects where no major renovations are planned, the building owner must be aware that the project cost is increased.
Integral LED fixtures are extremely efficient because their geometry is designed to maximise lighting output. For example, it is possible to replace a fixture with three T8 fluorescent tubes, consuming over 90 watts in total, with an LED panels that only draws 45 watts that yields savings of over 50 percent. These fixtures also offer a remarkable service life: some models are rated for up to 100,000 hours, which is equivalent to more than a decade of continuous operation.
When office lighting will be upgraded to LED, both tube upgrades and fixture upgrades are viable options. The advantages of a tube replacement are low cost, fast installation and minimal disruption; while a fixture replacement offers a higher efficiency and service life.
The energy savings achieved with a tube replacement can range from 30 to 50 percent, while a fixture upgrade can offer savings from 40 percent onwards. The service life in both cases is far superior to that of conventional T8 lamps: LED tubes offer up to 50,000 hours, and LED fixtures up to 100,000 hours.
Although LED lighting is normally associated with energy savings, the technology also has potential to improve Internet communications significantly.
There is an emerging concept called Visible Light Communication (VLC), which consists on using light pulses for wireless data transmission, just like Wi-Fi signals but with significant advantages in terms of speed, bandwidth and security.
Li-Fi is a subtype of VLC, and it could potentially succeed Wi-Fi as our main form of wireless communication. Li-Fi signals can be distributed through LED fixtures as light pulses that are invisible to the human eye but can be picked up by sensors in connected devices.
Li-Fi Offers a Much Wider Spectrum than Wi-Fi
Wi-Fi communication has successfully met the data transmission needs of human society, but the Internet of Things will bring new challenges, as billions of new devices are brought online throughout the world. Wi-Fi uses the radiofrequency spectrum for communication, and it is becoming saturated as the number of connected devices grows.
On the other hand, Li-Fi uses the visible light spectrum, which is around 10,000 times broader than the RF spectrum. This means that Li-Fi is better suited to accommodate the large number of devices that will be brought online as the IoT becomes mainstream.
Speed Advantage of Li-Fi Over Wi-Fi
The Internet of Things will not only require a much broader frequency spectrum to transmit data, it will also be necessary to handle much larger volumes of information. Experimental Li-Fi products have already achieved data transmission speeds exceeding 10 gigabits per second, far beyond the capabilities of Wi-Fi, which has maximum speeds of around 300 megabits per second; in other words, Li-Fi is more than 30 times faster and still has plenty of potential to evolve.
Thanks to their bandwidth and speed, Li-Fi and other VLC technologies can potentially become the backbone of the Internet of Things, and each LED fixture can become a communication hub. If connected devices are equipped with optical sensors and emitters, they can interface with the nearest LED fixture and become part of a Li-Fi network.
Safety Advantage of Li-Fi Signals
Li-Fi requires a direct line of sight between the connected device and an LED fixture. This might seem like a disadvantage, considering how Wi-Fi can go through walls and opaque objects, but there are several benefits:
- The inability of Li-Fi to cross walls is compensated by the fact that lighting fixtures are everywhere in built environments, both indoors and outdoors.
- Privacy and data security will be enhanced. For example, hackers will require direct line of sight to access a specific Li-Fi fixture.
- The total cost of electrical installations and data networks will be greatly reduced, as lighting and wireless communication are unified into a single system.
Visible Light Communication will turn LED lighting into a much more valuable technology, which will not only save energy, but will also provide communication services at much faster speeds than current Wi-Fi networks.
Upgrading to LED lighting gives companies a solid return on investment, but doing so also brings significant environmental benefits.
With their low energy consumption, LED lamps and fixtures help reduce the demand on power plants, which often run on fossil fuels. In addition, LED technology generates less waste than other types of lighting.
Environmental stewardship contributes to sustainability, but it also improves the brand image of companies. For many clients, this is a very important factor when deciding who they will conduct business with.
How LED Lighting Helps Reduce the Load on Power Plants
Generating energy has an environmental impact, and this applies for all generation technologies. Even renewable sources such as wind, solar and hydroelectric power have an environmental impact, because even though their operation is clean, it is necessary to disrupt the local ecosystem during construction. Hence, the cleanest energy is that which is never consumed, and LED lighting helps reduce the energy footprint of human activity.
Upgrading a single lighting fixture to LED does not have a noticeable effect on the power grid, but large-scale adoption of the technology can have a considerable impact. For example, assume you replace a 96-watt fluorescent fixture with a more efficient LED product that only draws 50 watts, saving 46 watts per fixture. Although 46 watts is very little power, the effect can be significant when LED lighting is deployed at a larger scale: if this upgrade is carried out for 50 buildings, with an average of 1000 fixtures each, the total power consumption is reduced by 2.3 million watts, or 2.3 megawatts. Even with a power grid running completely on renewable sources, saving 2.3 MW means not having a few wind turbines or several thousand photovoltaic panels. Of course, the benefit is ever greater if these 2.3 MW are subtracted from the load of a coal power plant.
LED Lighting Generates Less Waste
Older lighting products often use hazardous materials, and these are released into the environment once the lamps reach the end of their service life. For example, fluorescent lamps contain small amounts of mercury, a highly toxic element. In addition, even if a lamp is free from hazardous compounds, its disposal normally involves non-biodegradable waste.
LED lighting offers several advantages in this aspect:
- LED lamps have a very long service life, and less waste is generated for the simple reason that replacements are much less frequent. For example, an LED bulb rated for 25,000 hours replaces over 20 incandescent lamps during its service life.
- Many of the components in LED lamps can be recycled. In other words, waste is generated with less frequency, and a significant portion can be reused for new lamps and fixtures.
LED lighting is greener than older lighting technologies thanks to its low power consumption and reduced waste generation. In general, a city that makes ample use of LED technology will produce less emissions and waste than one using HID, fluorescent and incandescent lighting.