Achieving the Promise of Long Life in LED Luminaires

Imagine a luminaire that can provide energy-efficient, dimmable, code-compliant light for 10 years or more before the light source needs to be replaced. That could make a real difference to your occupants, your operations, your bottom line. Maybe you could better utilize your maintenance staff, or, if your crews are being paid overtime to change lamps after-hours, reduce labor costs. No more lighting contracts. No more storage of burnt-out fluorescent lamps. And in the competition for tenants, especially triple-net tenants, reduced utility bills and maintenance costs increase your competitive edge and the value of your property.

Finelite provides a 10-year warranty with our LED luminaires. It is important to note that this is a performance based warranty covering all of the key components: the LED light engine, the LED driver, the diffusers and the luminaire body. Finelite is different because we don’t talk about x number of LEDs failing before the warranty kicks in. Nor do we exclude key components because they are not manufactured by us. Instead, we cover the fixture and its key components completely. This is a company you can count on.

10 year warranties require superior luminaires. So how do you compare them? Below are some important characteristics you should be looking for.

LED Lifetime Ratings

A funny thing about LEDs: they don’t “burn-out” the way incandescent and fluorescent lamps do. Over time, LEDs fade. This fading is quantified in the lighting industry as L_p where P is the percentage of light loss when compared to the initial light output of the brand new luminaire, over a specified amount of time. Some typical L_p values are:

L₇₀ – 70% of initial light output, or a 30% loss of illumination,
L₈₀ – 80% of initial light output, or a 20% loss of illumination,
L₉₀ – 90% of initial light output, or a 10% loss of illumination, and so forth…

What is the difference between a luminaire rated L₉₀ for 100,000 hours and one rated L₇₀ for 50,000 hours?

The best luminaires in the industry achieve L₉₀ for 100,000 hours which means that the light output will diminish only 10% over the course of 100,000 hours of operation. Most luminaires achieve far less. L₇₀ for 50,000 hours, a common warranty duration, means that the light output will diminish 30% over the course of 50,000 hours.

Component Lifetime

The key components affecting LED luminaire lifetime are the LED driver and the LED light engine. Heat impacts the life of these components, and, as you might expect, the cooler the component operating temperature, the longer the lifetime. Finelite designs luminaires to minimize heat. Let’s investigate the how heat affects LED and driver life.

LED Drivers

The lifetime of an LED driver is a function of the temperature at which it operates. Run the driver cool (around 50˚ to 55˚C) by keeping the driver mechanically heat-sinked and you will get driver lifetimes in excess of 100,000 hours. Run the driver hot, 75˚ to 80˚C and lifetime will be reduced by almost 70% to 35,000 to 50,000 hours!

OSRAM SYLVANIA Application Note, “Understanding the Lifetime of SSL Systems”, LED348

Mid-powered LEDs

Heat is the factor dominating all others when it comes to LED module lifetime, too. While it helps to understand the physical components of an LED module, we can simplify the issue by stating that high-powered LEDs with high lumen outputs requiring high drive currents run much hotter and have significantly shorter lifetimes than mid-powered LEDs with lower lumen output using low drive currents. For greater technical depth, please follow the links provided at the end of this application note.

1 to 5 watts concentrated on one LED package requires a heat sink

0.1 to 0.3 watts on a wide spread matrix does not require a heat sink (Finelite)

Finelite LED luminaires use many mid-power LEDs modules using a low current, to create the same lumen output as fewer high-power LED modules using a high current. Finelite’s LEDs run so cool that heat sinks are unnecessary.

Summing It Up

LED luminaires have the potential to last decades so it is important to select your partners carefully and you need to understand the warranty. Is it performance-based or failure-based? Remember: LEDs don’t fail, they fade. Does the warranty cover all of the critical components—LED light engine, LED driver, lens/diffusers, body—or does it exclude some components? made by other manufacturers?

Finelite has been making affordable, energy-efficient luminaire for offices, education and healthcare for 23 years. As LED technology stabilized we began working with the DOE to develop best practices. We are proud to offer the best warranty in the industry. And beyond our warranty we offer what we call:

The Finelite LED Difference