Why I Replaced All the Lightbulbs in My House with Red Ones

Sean Knight
3 min readMar 2

And you should too

Photo by Varvara Grabova on Unsplash

It all started one weekend where we lost power midway through the day.

As the evening crept on I noticed myself feeling sleepier than usual. Heck, I was downright tired. It had been years since I had felt that sleepy without taking Melatonin or some other exogenous supplement or sitting in front of some Netflix show until I can no longer follow the plot.

It made me think of what it’s like when camping. After the sun goes down, sure you have flashlights and phones, but you really can’t escape the fullness of it being nighttime.

So the next thing to do was obvious. After a great night of sleep I went down the research rabbit hole to figure out why artificial lighting seemed to keep me from getting tired.

That’s when I discovered that it’s not actually about the light but instead about the blue and green parts of the light spectrum. And that red light may help promote sleep.

Through this frenzy of research, I found out that red light has less of an impact on your sleep cycles than other types of light because it has a longer wavelength and lower frequency. This means that it produces less energy and is less likely to stimulate the cells in your eyes that regulate your circadian rhythm.

The cells in your eyes that regulate your circadian rhythm are called intrinsically photosensitive retinal ganglion cells (ipRGCs), and they are most sensitive to blue and green light. When these cells are stimulated by blue or green light, they send a signal to the brain to suppress the production of melatonin, a hormone that helps you fall asleep.

Red light, on the other hand, has a longer wavelength and lower frequency than blue or green light, which means that it produces less energy and is less likely to stimulate the ipRGCs in your eyes. As a result, exposure to red light is less likely to interfere with your sleep cycles.

That’s when I got the crazy idea to replace all the lightbulbs in my house with red ones.

If you want to have extraordinary sleep — especially in a world where most people are sleep deprived — you will need to stop doing ordinary things.

Sean Knight

Physicist doing non-physics things