Dark Mode may not be a silver bullet to improve battery life

Dark mode has been touted as one of the best features of today’s phones, allowing devices with OLED displays to save power compared to using a typical lighting mode. . This is because OLED displays can turn off individual pixels to display black colors, thus saving juice.

However, a new study by researchers at Purdue University has shown that switching to dark mode might not make a big difference to power consumption with typical use.

The researchers looked at six apps, namely Calculator, Google Calendar, Google Maps, Google News, Google Phone, and YouTube, using their new tool called Per-Frame OLED Power Profiler (PFOP). The team then took a look at how Dark Mode affected one minute of activity for each app on the Pixel 2, Pixel 4, Pixel 5, and Moto Z3.

Related: Do you like dark mode? Here’s why you might want to avoid it

The result? Well, the team found that many consumers use automatic brightness settings that keep the brightness around “30-40%” indoors. But the researchers said switching from bright mode at 30-50% brightness to dark mode only saves 3-9% energy on average for all devices tested.

However, the study found that users would see greater energy savings if they switched from a bright high-brightness mode to a dark mode. In fact, he noted that switching from a bright mode with 100% brightness (as you would expect outside in the sun) to a dark mode could save 39-47% in juice. That’s a major gain that could translate into more than a few extra minutes of power.

The study also claimed that Android’s battery consumption feature does not take dark mode into account when calculating an app’s power consumption. The team says they have developed a tool, called Android Battery +, which takes dark mode into account. Purdue researchers say they plan to open the PFOP tool and add the Android Battery + feature to the Android Open Source project. The Battery + feature is highlighted in the red box in the image below.

Some of these results seem obvious, however, as we already know that considerably high brightness in bright mode can eat away at a phone’s battery. So it stands to reason that you would see higher gains switching from a bright mode to a very high brightness to a dark mode than to switching from a bright mode to a moderate brightness. Google even illustrated the relationship between dark mode and brightness with its own research in 2018.

But what’s interesting is how little difference Dark Mode can make if you prefer low to medium light anyway. Therefore, those who don’t crank up their phone’s brightness in the first place might not want to go dark mode if they’re hoping for big power gains.

We would also like this test to be done using the same brightness measurement for each device (based on nits), as some phones have brighter screens than others. So, 100% brightness on one phone may not be as bright as 100% brightness on another.