The Guardian's Samuel Gibbs performed a week-long test using an iPhone 6S, and found that by removing the app, he was able to save up to 15% in battery life.

There have been numerous tips and tricks on how to save battery life on your phone but there may be a better way to save as much as 20% more juice on your phone - stop using the Facebook app.
In line with Android Authority's discovery last month, which showed that the Facebook app could drain Android smartphone batteries by as much as 20%, The Guardian's Samuel Gibbs also performed a week-long test using an iPhone 6S, and found that by removing the app, he was able to save up to 15% in battery life.

Read more: http://www.istylmagazine.com/news/technology/check-out-why-deleting-the-facebook-app-on-your-phone-can-save-you-more-battery/