It may explain why, for the first time, Rovio posted both a free and paid version of one of its Angry Birds apps, Angry Birds Space, in Google Play. Although Rovio has had paid version of Angry Birds, Angry Birds Seasons, and Angry Birds Rio in the Amazon Appstore, it hasn't had any in Google Play --- until now.
Research done by Purdue University, focused on Windows Phone and Android, showed that ad-supported apps can use as much as 70 to 90 percent of the energy they draw for uploading information (for ad targeting) and downloading ads.
That includes Angry Birds, which uses 70 percent of the power it draws for ads.
Although you'd have to assume that the same situation exists on any ad-supported iOS apps, this is a big problem for Android, where developers have found it much more of a challenge to convince users to pay for apps, as opposed to iOS. If there are paid and free versions available, we ourselves typically opt for the paid version, as we want to support Android developers.
Now, with this new study, it seems that paying for an app does more than just support developers. It supports your battery life, too.