Controlling LEDs

LEDs.gifLED light sources offer energy savings, long life, excellent light quality, and new fixture options— allowing them to be used in almost any application. These advantages make LEDs an excellent choice for virtually any customer, but there are challenges associated with making sure that LEDs meet end-user expectations. Incandescent and halogen lighting, while inefficient, always offered highly predictable light quality with any control. In comparison, LEDs are much more efficient, but their dimming performance can widely by manufacturer and model.

When selecting LED products, issues with dimming compatibility probably create the greatest source of frustration. Ensuring compatibility between LED lamps, fixtures, and controls can be confusing, and if not done properly, lighting performance will suffer. To avoid callbacks and ensure a happy customer, contractors have to choose the right combination of LED loads and controls.


For many customers, energy savings is top-of-mind. LEDs are energy efficient by design, and a simple LED lighting retrofit can help meet building and energy codes while reducing electricity consumption. So why include dimming control with LEDs? For the same reasons you would use dimming control on any light source – to maximize energy savings, extend system life, enhance flexibility, increase productivity, and provide a comfortable environment for building occupants. Regardless of the solution, from a single switch or dimmer to a centralized lighting control system, a bit of research can help guarantee compatibility and satisfactory performance, eliminating many of the common concerns and issues that can be seen with LED installations.

Similar to fluorescent sources, dimming LEDs saves energy at a roughly 1:1 ratio (see figure 1). For example, if you dim LEDs down to 50 percent of their light output, you save nearly 50 percent of the associated energy use.

Dimming LEDs also makes them run cooler, further extending the life of both the driver and the phosphor in the LEDs. This can double or triple the useful life of this already long-life source.


There is a broad spectrum of LED lamp and fixture manufacturers, providing solutions of differing price, performance, and quality. Likewise, not all controls will perform equally or are equally suitable for use with LEDs.

If all the parts and pieces are not properly selected, the result can be “dimmable” LEDs that do not work as claimed, that never turn off completely, or that flicker, pop on, or drop out, leaving the end-user unsatisfied and you with a costly call back to the job.


Answering a few simple questions can help align a customer’s expectations with the performance of a given LED dimming system. Look to product packaging and manufacturer support options to help provide the information you need.

1. What is the application type – retrofit or new construction?

New construction enables you to use either LED bulbs or LED fixtures, allowing a wide variety of control options. Retrofit applications are often limited to LED bulbs, and the control options will be limited as well.

LED bulbs with Edison-base sockets are usually the lowest-cost option. They generally replace standard incandescent or CFL bulbs, making them especially suitable for retrofits. These lamps have integral drivers that determine whether they are dimmable and define the dimming performance.

LED fixtures can vary from cove lights to down lights and usually have an external driver mounted on their enclosure. Some fixtur