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If you were one of the early adopters of LED lighting, prior to 2014, chances are your lighting system may need a revisit. Wait...what?! Isn’t LED lighting supposed to last forever? Well, yes but…
My, My, Hey Hey (Neil Young and Crazy Horse)
[Is it] better to burn out than fade away?
With respect to Neil Young, fading away is one of reasons LED technology is so enticing. LED technology does not catastrophically fail. Instead, it diminishes in output little by little over time. In industry parlance, this is called L70, which is a measure of percentage degradation over time. L70 50k hours simply means the lumen output is expected to reach 70% of initial output at 50,000 hrs. – and 70% initial output is the recommended replacement threshold.
By the Numbers
Dividing 50K hours by your operating hours will get you the number of years of useful life of your LED system (12.5 years at 4000 hrs./yr. versus 16 2/3 years at 3000 hrs./yr.). So, if your LED lighting system was installed more than 10 years ago, it may be approaching the end of its useful life.
Purple Haze
Another consideration of LED useful life may be color shift. LED lighting doesn’t emit the “warm” or “cool” color white-light naturally. Most likely a phosphor coating has been applied to covert blue or purple light into white light at the various color temperatures (2700 kelvin and below for warm and 4000 kelvin and above for “cool”). Color mixing of Red, Green, and Blue LEDs is another way to produce white light, but due to the cost and complexity of these systems, they are rarely used. Over the years, this phosphor coating gets attacked by heat and UV (both biproducts of LED lighting) which may result in shifting the color temperature of your LED lights or, in drastic cases, eroding the phosphors altogether. If you have heard about the anecdotal instances of LED streetlights turning purple, this may be the cause. In most cases, especially for systems that do not have good thermal management, your system may experience a color shift especially when viewed against other products in the installation.
Weakest Link
Your LED system is comprised of an LED package (chip), mounted to a substrate or board, with a “driver” that delivers the correct power supply. LED drivers can be internal to the system, such as an LED bulb, allowing you to simply screw the bulb into the socket just like an incandescent bulb, or it can be external. In most commercial applications, the driver is external. Here again, heat is the enemy. High heat can cause the driver to fail prematurely. In most cases, the combined LED system has a warranty of 5 yrs. This is due to the life expectancy of the driver, which is often the weakest link in the system in terms of life expectancy.
Type A, B, and C Retrofits
An LED retrofit solution many institutions employed was to simply replace the fluorescent tubes in their existing fixtures with LED tubes. The existing ballast remained in place. This system is called a Type A retrofit. The LED lamp, in this case, has an internal driver that is designed to work with the existing ballast. The advantage of this system is that the entire system did not need to be replaced, and nothing needed to be rewired. The disadvantage of this system is that they relied on the useful life of the existing ballast and again, it may be approaching the end of its useful life.
Nowadays, many LED retrofits will also involve new drivers. These systems are called Type B or C retrofits. In type B retrofits, these LED tubes come equipped with an internal LED driver that allows them to be fed directly from main voltage. However, because they are fed directly from main voltage, they require rewiring and extra safety precautions.
A third type of retrofit solution is called Type C. These retrofit tubes come with an external driver. The benefit of an external driver is they allow the lamp to operate to their full capabilities in terms of efficacy, lifespan, and usefulness such as dimming capability.
New LEDs versus Old
According to the US Department of Energy, LED systems in the early Tens were somewhere around 50 lm/W – a measure of how much light is produced (lumens) versus energy consumed (Watts). However, these figures were based on raw LEDs. System efficacy, which includes driver losses, optics losses, and thermal losses would have been somewhere around 35-40lm/W. Today, it’s not hard to find LED systems at 100lm/W or greater. This means that any earlier LED system producing 2500lm would have consumed approximately 62.5W (2500lm/62.5W = 40lm/W). In 2024, this same system would consume 25W (2500lm/25W = 100lm/W) – a savings of 37.5W over the earlier system.
However, energy savings is not the only advantage of newer LED systems versus older systems. With advancements in wireless technology, you can now configure complex lighting zones wirelessly without having to run multiple feeds. Systems equipped with on-board sensors and digital drivers paired with external processors and wireless switches can be configured in almost any combination of complex zoning without the requirement of running multiple zone feeds. This drastically reduces the labor requirements to install and configure your system making it much more affordable versus previously zoned systems.
Conclusion
To conclude, if you were an early adopter of LED technology, congratulations. Without your enthusiasm there wouldn’t have been the demand that drove innovation that led to the exciting advancement we have today. But as early adopters of flat-screen TVs can tell you, there’s a useful life for everything. The good news, however, is that newer LED technology is vastly superior to early LED technology in terms of energy saving, utility, and cost. So, there are dramatic benefits of looking to see if your early LED system is due for an upgrade.
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