Replacing “light bulbs”, or lamps as we call them in the industry, used to be a simple task. You would look at the wattage and beam angle and replace it with something similar regardless of the brand. For example, if the lamp was a GE MR16 20-watt 36-degree, you could replace the lamp with an Ushio, Sylvania, Phillips, GE or any generic 20-watt 36-degree halogen lamp, and the light output would be like the other lamps in the systems. With LED lamps, this is no longer the case!
If an LED lamp fails, there are three critical specifications that must be considered: beam angle, color temperature, and lumen output. Beam angle refers to the width of the light output emitted from the lamp; a 90° beam angle is ¼ of a pie slice and a 30° is 1/12 of pie slice. Color temperature refers to the color of the light which can typically range of 2200K to 6000K. The lower the number the more yellow the light will appear, and the higher the number the cleaner crisp white/blue. See the color temperature (Kelvin) chart below for reference:
Historically we correlated a lamp’s light output with the wattage rating. We all know how much brighter a 100W light bulb is than a 60W light bulb. With LED lamps the amount of light output is measured in lumens. LED technology is rapidly progressing, and LEDs are becoming more and more energy efficient. Three years ago, a 7W LED might emit 350 lumens (50 lumens/watt). Today a 7W LED can produce up to 875 lumens or more (125 lumens+/watt)!
So, what does all this mean? If you have an LED lamp fail in your landscape lighting system, it’s pertinent that you replace the defective lamp with a similar color temperature, beam angle, and lumen output. Don’t ignore the wattage rating of the lamp that has failed but use it to find the manufacturer’s lumen output rating for the lamp. If you don’t follow these guidelines, your landscape and architectural lighting will not look the same.
For example - Just last week a contractor returned a defective Brilliance LED MR16 for replacement to out supplier. The lamp was 4th Generation 5W, 60°, 2700K MR16. This lamp uses 5 watts of energy and emits 2700K light in a 60° pattern. But more importantly, this lamp emits 320 lumens. This information can be found on the Brilliance LED specification sheets. Brilliance LED Gen 4 lamps are now obsolete, so to provide the customer with a similar “lighting effect” we had to find the right replacement.
The Brilliance LED Gen 5 lamps, released in January 2018, have different lumen outputs than their Gen 4 predecessors. The proper replacement for the defective lamp should be 60°, 2700K, and close to 320 lumens. In this case, we replaced the 5W Gen 4 with a 4W Gen 5 MR16, which is 325 lumens almost the exact same!
So, remember that when replacing a defective lamp in your LED lighting system you have to match the beam angle, color temperature, and light output (lumens). You can typically find the lumen output of the defective lamp on the manufacturer’s website. If you can’t find the lumen output of the defective lamp, you can test the output of a working lamp on the system using a lumen meter to ensure proper replacement.
The key here is that there is much more that goes into changing an LED bulb than a halogen and using a professional will ensure that this is done correctly and keep your system looking its best.