F.lux Review: The Software That Makes You Sleep Better

We have affiliate relationships where we are paid a commission on sales through some of our links. See our disclosures.
nightowl woman computer

Here’s a little thought experiment: How many technological innovations in the last 15 years have become indispensable in your daily lives? I can think of quite a few — the mobile phone, WiFi, GPS navigation, the internet, and many more.

Recently, I added a new invention to my list: A simple piece of computer software that I would now find hard to live without.

The Beginning of F.lux

You’d be forgiven if you’ve never heard of F.lux. It’s freeware, so you won’t have seen any advertising or marketing campaigns.

Despite being well under the radar, F.lux has a large, loyal, and enthusiastic base, as demonstrated by the thousands of comments on its download page. However, it’s not easy to describe in words why there are so many F.lux devotees. Like all religious cults, F.lux is an experiential process, so you really have to live it to truly understand.

What Does F.lux Do?

The tagline for this software is “Better lighting…for your computer.” However, this is a pretty broad idea, so many people miss the point completely. There’s a misconception that F.lux is a software version of the ambient light sensors found on most Apple products these days.

There’s actually a subtle and important distinction between these two products. Instead of adjusting the brightness, F.lux works discreetly in the background, automatically adjusting the color temperature of your screen. It adapts your computer’s display to the current time — “Warm at night and like sunlight during the day.” In effect, it tries to match the light from your computer to the light in your natural environment.

Why Do I Need F.lux?

In order to fully benefit from using F.lux, it’s useful to know a little of the science behind this app. Visible light is made up of different wavelengths which our eyes perceive as color. These colors can be represented on a “temperature scale,” which is measured in Kelvin (K). As the day progresses, the color temperature changes — think of the difference between a bright morning and a golden sunset.

Human beings have evolved alongside these daily light patterns, developing biological mechanisms to trigger sleep and wakefulness. When the light starts to fade at night, our bodies start producing melatonin, aka the “sleepy hormone.”

As morning approaches, daylight becomes a signal to stop producing melatonin, which makes us feel alert and awake. It’s a beautifully balanced symbiotic relationship with nature. So, what’s the problem? To put it simply, 21st century lifestyles don’t always treat this relationship with a whole lot of respect.

The Problem with Computers at Night

Computer screens, including smartphones and tablets, emit light in the blue part of the color spectrum. This doesn’t cause any issues in the daytime, but at night, this blue light limits the production of melatonin. In layman’s term, the bright light from your laptop/iPhone/iPad screws up your sleep-wake cycle.

If you want to know more about the science behind these phenomenon, the developers of F.lux have provided a great resource on their site.

BlueLightGlasses min

F.lux Settings

F.lux is designed to work unobtrusively in the background of your devices. Apart from the settings page, there are no controls or interfaces. Basically, the idea is you that you only have to set F.lux up once, and then you never have to touch it again. The app is cross-platform (with the exception of Android devices), so there are versions for Windows, Macs, Linux, and iOS.

To set F.lux up, the first thing you need to do is add your location. After doing this, the app calculates the time of sunset and sunrise wherever you are. Next, you will select what type of light you want your screen to replicate at night. You can select Tungsten, Fluorescent, or Halogen, or you could even choose your own custom value by adjusting the temperature sliders.

And that’s pretty much it. You can choose between a slow or fast transition between the day and night settings. Personally, I prefer slow, as you barely notice when the change occurs.

F.lux In Use

During the daytime, you shouldn’t notice any difference to your screen, unless you prefer to change the default daylight setting of 6,500K. However, as dusk approaches, your screen will gradually (if you have selected the slow setting) change to a warmer color setting, which is easier on the eyes at night.

The first time I tried F.lux, the only difference I noticed was that the screen seemed a little more red. It only took me a day or two to adjust to this new hue, and now I keep F.lux on 24/7. I would find it almost unimaginable to go back to my pre-F.lux display settings. I can’t really put it into words, but the effect of disabling F.lux at night is not unlike staring at the sun. However, if you do need to do any color sensitive work, like photo-editing, you can temporarily bypass the F.lux app.

Benefits of F.lux

After reading this review, I hope you can now see why I’m such a fan of this app. To sum things up, I wanted to share some of my favorite F.lux benefits.

  • F.lux helps to reduce eye strain when using your computer or tablet at night.
  • F.lux increases your productivity by allowing you to work later into the night, without eye pain.
  • F.lux reduces stimulated wakefulness by minimizing the effects of blue light, helping to keep your sleeping schedule stable.

As I mentioned earlier, F.lux is a bit of a strange concept to get your head around. You really just have to see for yourself what a difference this app makes. If you’re still skeptical, there’s no harm in giving it a tree, as it is completely free to the public. Maybe you’ll be pleasantly surprised!

Sleepopolis Team

The Sleepopolis team is all about helping you sleep better. We live, eat, breathe, and sleep (ha!) all things, well, sleep! Whether you need a new mattress, are having trouble sleeping, or are just tired of counting sheep, we've got you covered. Check back here often for the latest and greatest in mattress reviews, sleep news, or health tips, and in the meantime, sleep well.