iOS 27 battery drain: What to know

Catalina Lindgren Technology 15 Sep, 2026 Americas

iOS 27 is here, and like clockwork, the usual complaints about battery drain.

Apple iOS 27 update is seen displayed on a phone screen in this illustration photo

iOS 27 has started rolling out, bringing Siri AI, expanded Apple Intelligence, AI photo editing, and more customization options for Liquid Glass. Early reactions have been largely positive, but as with every major iOS release, some users are noticing their battery draining faster and their phone running warmer than usual in the days right after updating.

According to Apple's own support documentation, that's expected, not a sign anything's wrong. Immediately after a major software update, a device needs time to finish setting itself up in the background. That usually entails indexing files and data so that system-wide search works properly, downloading additional assets for new features, and updating apps to their latest versions.

All that background activity draws extra power and generates extra heat, which is why "battery life and thermal performance" can dip temporarily right after an update, according to Apple. Battery drain issues should also improve with future updates to iOS 27.

Apple also points out that new features themselves can shift how a phone uses power once setup is finished. Something like Siri AI leaning more heavily on on-device processing, or expanded Apple Intelligence features running more often, can mean the phone is simply doing more computational work day-to-day than it did before the update. Apple says it continues tuning this in follow-up updates to balance new capabilities against battery life.

This is nothing new after an iOS launch. We've covered this for the iOS 26 launch, iOS 18, and even iOS 17.

Given how consistently this happens every year, it's less "new problem with iOS 27" and more "the normal cost of updating," and it's generally not something worth panicking over.

Preorder the new Apple products

Along with iOS 27, Apple also released new AirPods, Apple Watches, and iPhones. Except for the iPhone Duo, all of these devices are available for preorder now.