Is Light Flicker in the Office Causing Your Headaches?

Office with cubicles and overhead fluorescent lights

Have you ever wondered why your eyes and head sometimes hurt after sitting in your office for awhile? Look up at the lights for a possible answer. You may not notice anything other than a fluorescent fixture. But what’s happening inside the fluorescent tubes is fluctuating light output. Input power frequency variations inherent in the relationship between the magnetic ballast and the lamps cause the fluctuations. The pulse is too rapid for most people to see. However, some people sense the pulse and have a physical reaction. The same flicker may occur with screw base CFLs that have an integrated magnetic ballast.

Normally the flicker problem is greatest with T12 fluorescent lamps and magnetic ballasts. People report far few flicker issues with T8 fluorescent lamps and electronic ballasts. The best solution both for the flicker and for increased energy savings is to retrofit your fixtures to T8 lamps with high efficiency electronic ballasts. Likewise, CFLs with integrated electronic ballasts will have reduced flicker.

By contrast, incandescent and halogen bulbs do not cause flicker. A heated filament (usually tungsten) produces light. No ballast is involved. It’s simply electricity into the filament and the bulb is illuminated.

Similarly light emitting diodes or LEDs produce extremely stable light output. LEDs are semiconductors. When electrons move through the semiconductor, out comes light, without flicker.

If you are extremely sensitive to flicker, avoid fluorescent lights. You should have no problem with either incandescent, halogen or LED.

The following two tabs change content below.

Dave Burtner

Dave has been active in the lighting industry since 1994. Formerly a member of the Illuminating Engineering Society of North America and certified by the National Council On Qualifications for Lighting Professionals, Dave now writes blog posts, lighting tips and provides lighting product assistance for the Topbulb website.