Our “Smart” Devices Still Have a Blue Light Problem — But There Are Solutions

Amber Case
5 min readJul 11, 2024

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Many appliances often glow bright blue at night.

I recently spent the night at a friend’s house. With gorgeous throw rugs and tasteful wall art, he had done everything possible to create a perfectly inviting, cozy space.

Unfortunately, the toilet had other plans.

An expensive new “smart” appliance, the bidet toilet boasted the latest comfort and sanitation features. But as I discovered when using it in the middle of the night, it also has a piercingly bright blue light that shouted into my eyeballs when I opened it.

After I closed the toilet lid, a massive black spot blotted my vision. I actually had to wait a few minutes before I could see well enough to safely return to bed. By then, my circadian rhythm had been so disrupted, it almost took an hour to get back to sleep. I woke up groggy and cranky.

I wasn’t the only one to have this issue. On Reddit, someone compared the blue light on their expensive Toto Washlet to “an airport runway”, And there was no way to shut it off.

I can’t blame my friend for the poor sleep; they’d done everything possible to make their home welcoming, even spending quite a lot of money to upgrade their bathroom with a premium appliance. I blame one of the most common design mistakes we still see everywhere: using blue light in appliances intended for night use or the home.

It’s a frequently-cited flag in first draft of the Calm Tech Institute certification process for home automation devices: The bright blue light of flat, rectangular touch screens, fans, and displays may look appealing, but can be annoying in home products. Blue light inhibits the production of melatonin, the hormone that regulates our sleep cycles. Blue light before bedtime can wreak havoc on our ability to fall asleep. Harvard researchers conducted an experiment comparing the effects of prolonged blue light vs. green light exposure and found that the former suppressed melatonin and shifted circadian rhythms by twice as much.

Despite this research, we still see blue light in many multiple home devices. To name just a couple more:

If I seem personally frustrated by this phenomena, it’s because I wrote a long essay for FastCompany Design, “Why tech’s favorite color is making us all miserable”, back in 2018. An editor there later told me it became one of the most read articles of the year, viewed over a million times, and shared widely by designers. I was hopeful we’d see a substantial shift away from blue light. Its hold on our imaginations, however, remains hard to break. Thanks to influential pop culture totems like Blade Runner, we still see blue light as “the color of the future”.

Part of the problem, to be sure, is that mass consumer products are often designed many years in advance, and it’s incredibly costly to manually switch out blue lights on appliances already in production or in retail stores.

Fortunately there are some solutions:

Orange Shift

The color of light is a crucial factor to keep in mind during the product design phase (and integral to the CTI certification process.)

Orange light is ideal for dark/night time contexts. It’s frequently used by the military, where being able to read an indicator accurately (and without eye strain for long hours late at night) is literally a matter of life and death. As I wrote in that FastCo essay:

F-111 Cockpit Source: Wikimedia.

It could be argued that the average person today manages as much information with their devices as an intelligence officer in a wartime situation. But from the Cold War up to now, the user experience of military and consumer technology is vastly different.

Airplane cockpits, submarines, and other military-grade systems are specifically designed for information density, with primary, secondary and tertiary information sources. A key difference in all of these interfaces is color–by and large, many military displays are deep red or orange.

Products with Night Modes and Indicator Options

Websites have night modes now, after all, why not appliances?

An increasing number of products have Night Modes, like the Winix air purifier. The appliance shows air quality status through indicator lights, which can glow bright at night. But

Winix also has a sleep mode that allows the Air Quality Indicator light to turn off.

LED Light Stickers

A short term fix for consumers, depending on the bulb size, are LED light stickers, which allow some of the light through or block it all, allowing for bright blue lights to dim.

Bright light dimming stickers.

For product manufacturers with blue light appliances already on the market / in production, it’s not too late to address the issue: We recommend offering or including to install orange warming filters like these to customers, advising their use when a blue lit appliance is in areas of the home which are visible at night. Extremely low cost, they’re an easy and powerful way to help build brand loyalty — and preempt customer complaints over disrupted nights.

In case you missed it, the FastCo blue light essay is also available on my Medium here.

Disclosure: This post contains an affiliate code for light dimming stickers on Amazon and an air filtering system.

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Amber Case
Amber Case

Written by Amber Case

Design advocate, founder of the Calm Technology Institute, speaker and author of Calm Technology. Former Research Fellow at MIT Media Lab and Harvard BKC.

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