Lighting Technology of the Millennium: Switching Out Old Lights for LEDs

Lighting Technology of the Millennium: Switching out Old Lights for LEDs

At the end of the 19th and the beginning of the 20th centuries, incandescent lamps and lighting were the new technology, and everyone was converting from natural gas lighting to electricity. By the beginning of the 1940s, fluorescent lighting was the latest technology, and many installations in residential, commercial and industrial facilities were converting from incandescent to fluorescent. Fluorescent lighting was touted as the world’s best and only lighting of the midcentury. No other lighting would ever be invented that was better—until it was!

In 1962, General Electric engineer Nick Holonyak Jr. invented the first visible spectrum light emitting diode (LED). LED lighting uses 80 percent less energy than incandescent lights since 95 percent of the energy in LEDs is converted into light and only 5 percent is wasted as heat. There are other experimental lighting technologies being developed, however. LEDs have been incorporated into the National Electrical Code (NEC) and are on shelves in almost every store that carries lamps.

Many homeowners are converting their old incandescent and fluorescent luminaires to LED lighting. Electrical contractors are being asked to not only install this new technology but often to explain the function of these LEDs and why their installation may require extra work to operate properly with existing switches and dimmers. Here is the rest of the story.

While LEDs are one of the most common lighting types available, dimming these units may be an issue with some older dimmers already installed in homes. LED lamps are dimmable and operate at much lower power or wattage. The dimming range of incandescent lamps is around 100 percent while LEDs may be 10 percent to 30 percent less at around 70 percent. There are some reports of old-style dimmers, those that are not specifically designed for dimming LEDs, causing flickering from small fluctuations of power. Plus, the dimming range will be different for LEDs than for incandescent lamps.

Many of the new dimmers on the market are specifically designed for LEDs, will alleviate the flicker that was a common problem, and will still work appropriately on incandescent lamps. Make sure, when installing LED lamps and lighting, that the new lighting will work well with the existing dimmers or replace them with a new style dimmer. In addition, always make sure that whatever  dimmer you use is within wattage load so the dimmer rating is not exceeded.

There are many different types of dimmers, including slide, digital and wireless. Some of these dimmers are compatible with incandescent, compact fluorescent lamps (CFLs) and LEDs, while others are compatible with LEDs exclusively. To be sure that the dimmer is compatible with LEDs, many manufacturers actually mark the dimmer range and compatibility on the yoke of the dimmer.

Once all of the issues between incandescent lamps, fluorescent lamps, LEDs and dimmers have been resolved, the electrician is now ready to start replacing lamps and luminaires in the home. It may be as simple as unscrewing the incandescent lamp and replacing it with the LED lamp.

Most listed table lamps, floor lamps, surface luminaires and recessed luminaires will have a maximum incandescent lamp size marking, such as 60 watt (W) maximum “A” lamp, and some will have a maximum CFL size, such as maximum 13W CFL. This marking is critical to ensure those sizes are not exceeded since the heat of the lamps and the transfer of that heat in these luminaires may cause damage to the lamp holder and the conductors connected to the lamp holder, ultimately causing a fire.

Incandescent lamps and CFLs produce substantial heat. LEDs, on the other hand, put off considerably less heat and cause less damage to lamp holder and conductors. Can a person install a regular screw-in LED lamp into a lamp holder with an incandescent rating not to exceed 60W or a CFL rating not to exceed 13W? The LED lamp will have a wattage rating on the lamp and the package containing the lamp with another marking, for example, that states “100W LED Equivalent.” This 100W marking does not mean that the LED is using 100W of energy, but that it gives off as much illumination as a 100W incandescent lamp.

If the marking on the luminaire is for maximum incandescent or maximum CFL, the LED lamp should not exceed the luminaire’s actual wattage rating. For example, if the luminaire states “not to exceed 60W incandescent,” an LED lamp of an equivalent rating of 100W would be acceptable.

An understanding of the new luminaires and lamps will help you create appropriate levels of illumination, while maintaining a safe installation in the home.

About the Author

Mark C. Ode

Fire/Life Safety, Residential and Code Contributor

Mark C. Ode is a lead engineering associate for Energy & Power Technologies at Underwriters Laboratories Inc. and can be reached at 919.949.2576 and

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