I first noticed being sensitive to flickering lights in 2009, when LED lighting was just becoming established. As the prevalence of LED lighting has increased, so has the issue. It’s not that the LED lighting technology itself is problematic, it’s that many manufacturers make fixtures that flicker on and off very quickly in a common technique called pulse width modulation (PWM) to control brightness instead of keeping the fixture a constant brightness. It’s a technique that can save expense in design, manufacturing, and operation, and most people don’t even notice it. But for those that can see it, it is crazy-making! Imagine for a moment if your local grocery store installed disco strobe lights instead of light bulbs, and left them running all the time. It’s awful.

Automobiles: One important example is that in 2022, most new cars are sporting LED tail lights and running lights that flicker. When the driver uses the brakes, the lights are at full power and don’t flicker, but to make the lights dimmer to act as tail lights, the lights are turned on and off hundreds of times a second. It’s a safety hazard for me. When those lights are in my eyes, I have to constantly redouble my attention on the road. It is a very safe bet that the flicker in car lights has caused accidents due to distraction and drivers having difficulty tracking vehicles.

Residential: Some of the LED lights we buy to replace incandescent bulbs flicker a lot, some flicker a little, some not at all. There is no way to know until you bring them home and plug them in. This creates quite a bit of friction in the marketplace for flicker-sensitive consumers; buying lighting shouldn’t be like playing roulette. Many consumers can’t identify the flicker per se: a good friend told me how her parents didn’t notice the flickering lights in their home until she replaced them. They immediately noticed the difference and irritability and sleeping difficulties in the house immediately decreased! Listen to her story.

Commercial buildings: Increasingly, public buildings use LED lighting. Much of this lighting is terrific, the light looks great, the fixtures last a long time, and they save money compared to incandescent and even florescent lighting. But sometimes the new lighting is very bad for a percentage of the people. The first examples that come to mind are the West Branch of the Berkeley California Library and a local restaurant called Bangkok Jam in Berkeley, CA. Since Bangkok Jam replaced their lighting with flickering LEDs, I can’t stand to be in the restaurant for more than a few minutes. Hear Lee’s story about Bangkok Jam.

The West Branch Library was rebuilt in 2013 and the building won several awards, notably for being California’s First Net Zero Energy Library and for it’s innovative, efficient lighting. No one noticed that the lighting flickers like mad. I went there for an event last year and before I got to the front desk, I knew something was amiss. The lighting looks like a fast strobe light to me, raising my anxiety level with every minute in the building. I am sure that is not what the builders intended!

At a rough estimate, 5-10% of people are bothered by flickering LED lights. Ask twenty of your friends and it is likely some of them will say “Oh yes, those new light drive me crazy! I thought I was the only one!”