Why We Chose NOT to Use LED Bulbs

From our archive (2015). Today we call this design a dedicated LED: the LED and driver are matched and built into the luminaire, but stay field serviceable.

LED has become the hottest buzz phrase in the lighting industry. LED bulbs are cheaper, easy to replace and easily interchangeable. However, for all the benefits, there are still many limitations. That's why Sterling Lighting's luminaires use dedicated LEDs instead.

Many people ask us how we came to this decision. It ultimately came down to one question: "What is best for our customers?" After considering our collective experience with LEDs, our engineers' advice and the mistakes of others manufacturing LEDs, we knew a dedicated LED was the best choice.

The problem with LED bulbs

The biggest issue with LED bulbs is heat. In our opinion, about 95% of LED bulbs installed in landscape lights are not designed for an enclosed fixture. Most LED MR16 bulbs are designed to have air circulate around them, such as in track lighting and recessed lights (a very popular use in Europe and Asia). Those fixtures don't encapsulate the bulb, so heat can dissipate.

Drawing heat away from the LED is a challenge every engineer faces when designing bulbs. That's why you often see heat sinks such as fins and air gaps built into LED bulbs. Tested alone in an ideal setting, like a laboratory, they perform very successfully. The problem is that an open-air indoor test is very different from a sunny, 100-degree day with the bulb inside an enclosed brass or aluminum fixture. The result is dramatically reduced performance on a property.

In fact, many bulbs see lumen depreciation in the first few months and burnout in the first year. This is not a new problem. One of the largest LED bulb companies told us they experience a 3% failure rate in the first year, and it only climbs from there, reaching 25–30% by the third year. For a landscape lighting professional who installs 100 systems a year with an average of 20 lights per system, the number of problem bulbs quickly becomes overwhelming.

Our experience with LED bulbs

We've encountered these problems ourselves. We began using LED bulbs in 2010. After testing bulbs from seven different original equipment manufacturers (OEMs), we settled on the one we believed was the highest quality. We saved 80% on energy and could use less wire and smaller transformers, but ultimately the failure rate was too high to make the bulbs worthwhile. Even though our OEM guaranteed the LED was designed for an enclosed fixture, the heat buildup was too great and the bulbs burned out.

Why is there a discrepancy?

It's a puzzling situation: if LED bulbs have major problems with heat dissipation, why are so many on the market supposedly designed for closed fixtures? One reason is that some OEMs are willing to bend the truth to make a sale. There are also design companies that roll the dice and use an LED bulb even when the OEM specifically states it isn't designed for an enclosed fixture. Ignoring the realities of the technology is simply not sustainable.

The solution

To give our customers the best option given these limitations, we had a few choices:

• Design an LED MR16 that could be used in an enclosed fixture. This would have required very low lumen output to reduce the risk of failure (which is why you see so many low-lumen bulbs on the market). But 200–350 lumens just isn't bright enough for many professional lighting designs.
• Design our own LED luminaire. This posed many challenges (perfectly matching the LED and driver to the luminaire, ease of changing parts, lumen output and more), but we knew it was the only way to ensure the quality we wanted.

So we took on the challenge and designed Sterling Lighting's signature LED luminaire with the best of both worlds: high lumen output, easy-to-change parts, premium components and proper heat sinking. That work led to our first dedicated LED luminaires in 2013, including the SL01 Up Light. Read the full story in What Is a Dedicated LED, Anyway?

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About the author: Patrick Harders, LC, is co-founder and CEO of Sterling Lighting and founder and principal lighting designer of Dayloom. He has more than 25 years of experience designing and installing outdoor lighting, and he's one of only five landscape lighting designers in North America with Lighting Certified (LC) accreditation. His projects have won multiple international lighting awards, including landscape lighting winners in 2018 and 2021, and he leads design of Sterling's luminaires.