The site used an iPhone 6s Plus for a week without the Facebook app installed and recorded the battery life at 10:30pm each night. The phone was taken off the charger at 7:30am and used normally, accessing Facebook for the same amount of time, and for the same purposes, via its mobile website.
On average I had 15% more battery left by 10.30pm each day. I had also saved space, because at the point I had deleted the Facebook app it had consumed around 500MB in total combining the 111MB of the app itself and its cache on the iPhone. To make sure that this wasn’t an isolated incident, I also recruited several other Facebook-using iPhone owners to conduct a similar test. They all found similar results, with increased battery life when using Facebook in Safari having uninstalled the main Facebook iOS app.
Facebook says its investigating the matter. Have you noticed excessive battery drain with the Facebook app installed?
Let us know in the comments!