So how long does a LED billboard light really last?

We have all heard the sales pitches in regards to LED light fixtures for you billboard. HUGE energy saving and very long life expectancies. The energy savings when calculated properly are simple math that can be backed up factually. The life expectancies however are a little more vague.

We would like to take a few minutes to explain how life expectancy of a LED light fixture is calculated and then apply some real world expectations for the billboard application.

When LED light fixtures first hit the market, many manufacturers and distributors were throwing out same crazy figures. We were hearing anywhere from 20 -40 years. Let’s face it, 40 years is a really long time for an electrical component to work in the field. So how did they come up with these wild numbers to tell the consumer?

In steps the Department of Energy for a little control. DOE developed a standard called LM80 to help consumers get a better understanding of the LED quality they were purchasing. Note I said the LED, not the fixture or light. The LM80 standard is a calculation that estimates the working life of the LED module.  Working life of the LED is considered to which the time the LED degrades to 70% of its initial lumen output. Since they have not been around for 40 years, the test is an estimate of performance and lumen depreciation over the first 6000 hours of life. From these results, the estimate is calculated on how long the LED will last.

So let’s take a pause and tie this back to the LED lights being sold to the billboard industry.  We essentially have three brands that make up any share of the marketplace. Holophane, LTI (aka Marquee), and the Cree. All three test out over 200,000 hours. How these numbers are reported to the consumer is quite different though the sales channel.

For this discussion, let’s discuss how Holophane came up with their expectations for the Sign Vue 2 LED family of light fixtures and then I will give you my opinion after the fact.  In the billboard business, we typically burn dusk to midnight. Some billboards have morning burn and others are all night illumination. There technically is no average hour per night, so let’s be liberal and say we burn on average 10 hours per night over the course of 1 year.  365 days *10 hours per night would be 3650 hours per year.

We have a fixture with a LM80 rating of over 200,000 hours. This is great you think, but you forget this is the LED, not the entire fixture and its components. So when developing the latest LED light, Holophane asked what is the weakest link in the entire LED system? The answer for all the LED billboard lights is the driver. The best drivers on the market are rated at 100,000 hours. Although drivers are inexpensively replaceable, Holophane used this number as a “serviceable life” expectancy for the fixture.

  • Driver life of 100,000 hours / 3650 hours per year = 27.39 years

Technically speaking the LED billboard light fixture should last 27 years. Now it is time for our opinion. Some say it’s a pessimistic approach and we might lose some sales to a fancy sales pitch, but we value our customer and I would much rather over-deliver than under deliver.  Let’s face it; a LED hanging off the side of a billboard is not in an ideal environment. When the LM testing is completed, it is performed in a lab. Oops, did they forget to tell you that. Billboards are hardly a lab environment. Power to the billboard is typically not the best (why the Sign Vue 2 LED has built in surge protection). UV degradation is high. (See my article on why a glass optic is best) Point being, we abuse our LED lights in the Outdoor Advertising market segment.

Here is what we believe is a realistic approach to calculation the life of the LED

  • Diver life of 100,000 hours / 3650 hours per year = 27.39 years
  • Cut that in half again and you get 13 years.

More than likely you are going to a significantly longer life but that is not the point. Point is using a simple payback the typical ROI on a LED billboard fixture using utility savings alone is 2.5 to 3.5 years. You have paid for this fixture 4 times over with just the utility savings. This does not include all the maintenance savings.  Over 13 years you would have replaced the lamp at least 3 times and the ballast once. When trying to figure out whether LED billboard fixtures are right for your Outdoor Company, using my calculations is a very safe bet. If the numbers make sense with this formula, it is a no brainer to upgrade your existing lights. If you have to use their exorbitant 40 plus year claims, you’re going to be disappointed in the long run.

For more information on LED life and deprecation