Posted on December 03, 2015

Throw-Back-Thursday! How is the life of an LED lamp determined?

Just a little throw-back this week to our post in 2012. Not much has changed in this aspect of the technology...except now, we have an LM-80 universal testing procudure that allows us to use a TM-21 estimation. This estimation then provides a more accurate life span for the LEDs that is catered to more specific situations and applications. Pretty cool stuff!

With traditional lamp sources like halogen, fluorescent and metal halide, a selection of lamps (usually somewhere around 100 samples) are burned continuously at a given voltage and position. When 50% of these lamps have ceased to function, then this determines the lamp life for that particular lamp. This does not mean that a given lamp will not burn out within an hour or another will last 3 times longer than the rated lamp life. This is just a method of determining the expected lamp life.

Applying a Different Approach to LED Lamps

The above method will not work for LED lamps because the actual LEDs will continue to produce light in diminishing amounts almost indefinitely. Therefore, a new method of determining the useful life of an LED was needed. 

The average human eye cannot detect decreases in light output over time until the light level reduces by 30% from its initial light level. Therefore, it was decided that 70% of the initial light output would be the determined life of LEDs. This is called L70.

However, L70 only tells you the useful life of the LED itself and does not take into account the components that power the LED or house the LED. Careful consideration is needed when selecting an LED lamp or fixture – taking into account whether the components themselves will last as long as the LED’s rated life.

That’s why at Solais, we have designed all of our components within our replacement lamps to last longer than the L70 rating of our LEDs. Therefore, our true expected life of our lamps is indeed the same as the L70.

About PowerSecure Lighting: PowerSecure Lighting designs and manufactures the lighting industry's highest-performing LED lamps and fixtures. With superior lumen output, center-beam candlepower, and overall aesthetics and performance, PowerSecure Lighting's LED products enhance the retail, supermarket, commercial, museum and hospitality environments of the world's leading brands. PowerSecure Lighting relentlessly pushes the innovation envelope to create products that replace traditional lighting technologies with zero compromise to aesthetics and performance. To learn more about PowerSecure Lighting, visit us in person in Stamford, Connecticut, or online at

Two of our new product lines are now available to order!
The XC3, XC5 and XC7 modular cylinders come in a variety of finishes and mounting options. The WW asymmetrical track wall wash fixtures come in two sizes. Yoke mount versions are coming soon!