Dark mode helps you save battery life, but you may not notice it

But while many people enable the setting because they believe it will extend the battery life of their phone (or other mobile device), research has now revealed that dark mode saves less energy than you might expect.

Modern smartphones feature a ‘dark mode’ setting that alters the appearance of what you see on-screen by using a theme with darker colors, especially black.

Highlights

  • Compared to LCD, the power an OLED display draws from a battery more directly reflects on-screen content. That allows the developers of an app or operating system to design a user interface that uses darker colors — with the aim of making their software more energy-efficient.

  • Dark mode only works on phones released over the last 5 years or so, as older screens had an LCD (liquid crystal display) that needed an extra backlight to illuminate pixels. By contrast, newer devices have an OLED (organic light-emitting diode) display that creates pixels without the external light source.

The new study, by PhD student Pranab Dash and Charlie Hu, a professor of electrical and computer engineering, was recently published in MobiSys ’21 (Proceedings of the 19th Annual International Conference on Mobile Systems).

To measure how dark modes affect the power draw and energy drain on batteries, researchers at Purdue University, Indiana, studied phones via activities that a person would typically perform while using six popular Google apps (Calculator, Calendar, Maps, Phone, News, YouTube) over 60 seconds.