Your iPhone or iPad is basically a small computer, but unlike larger desktop and laptop machines, it has no fan inside to keep everything cool. Like any other computer, your iPhone will generate heat — particularly when put under stress.
There are other reasons your iOS device might get hot. Today we’ll look at why, what you can do about it, and when you should start to worry.
Why Your iPhone or iPad Gets Hot
Relax. It’s normal for your device to get warm — even “hot” — when in constant use. This happens when you’re really taxing the hardware, examples of which include:
- Playing a demanding 3D game.
- Streaming high quality video for an extended period.
- Using processor-intensive apps like a synthesizer, digital audio workstation, or video editor.
- Making heavy use of GPS, particularly on older devices.
- During charging, especially combined with other activities on this list.
Like a computer, your iPhone or iPad kicks out heat. The two main components that generate heat are the system-on-chip (the equivalent to your computer’s CPU), and the battery. When the device creates heat, there’s no fan to cool it directly, and instead, the metal housing acts like one giant heatsink.
When your iPhone feels warm to the touch, it’s simply doing its job of moving heat away from the internal components. As the ARM chips used by Apple and similar manufacturers are so efficient in terms of heat production, they only really produce noticeable heat while being pushed to the limit over an extended period of time.
If you have your device in a case, as most of us do, then it might not be helping. It’s debatable whether Apple ever intended for people to hide their design with third party cases, but now their retail locations are full of them, and they even make their own. Buy an iPhone from an Apple retail location and you’ll likely be asked if you want to take a case as well before finishing your purchase.
So it’s unreasonable for cases to take the blame for heat issues, and generally they don’t pose a problem. But if you are noticing frequent overheating problems, you live or are travelling in a very hot climate, or you’re taxing your device while charging at the same time, you might want to consider losing the case to help the chassis better perform its job of dissipating that heat.
When Your Device Gets Too Hot
There’s a difference between warm and hot, and there’s an even greater difference between noticeable heat and too-hot-to-hold. iPhone, iPad and iPod Touch devices are designed to be used between 0ºc and 35ºc (32ºf to 95ºf). Use outside of these temperatures, either in very hot or cold temperatures, can cause problems.
If your iPhone gets too hot, you’ll see a message on screen to let you know, and many of the device’s main functions will be disabled or put into low-power mode. Last summer I left an iPhone in the sun with the screen facing up on a particularly hot day that was pushing 40ºc (104ºf). The iPhone in question was almost too hot to hold, and could’t be used for at least 15 minutes once it had cooled down in the shade.
Fortunately this caused no permanent damage to the iPhone, but allowing any device that contains a battery to reach high temperatures carries risks. The lithium ion batteries used in most smartphones and mobile electronics are relatively safe, but they’re still dangerous when exposed to extreme heat.
— FalciAdaptiveMotorsports (@FRRacingTeam) July 24, 2016
Leaving your iPhone in a car on a hot day, prolonged exposure to sun, and running demanding apps or use of GPS for extended periods while in a hot environment can all cause your device to display Apple’s temperature warning. You may be able to make emergency calls while this warning is on screen, provided the “slide for emergency” message appears.
To cool down a device that is too hot:
- Turn it off.
- Stop charging, if you are doing so.
- Remove any case you may be using.
- Take the device out of direct sunlight, into the shade.
- Wait for the heat to dissipate.
One thing you should never do to a hot iPhone is put it in the fridge, or any other environment that causes a rapid change in temperature. Rapid cooling can cause moisture in the air to condensate, which will cause water damage to the internal components. Always cool your device gradually, and avoid direct airflow from air conditioners on very hot days.
If Your Device Gets Hot All The Time
Heat generation is normal, but if your iPhone is hot most or all of the time, it may indicate a problem with iOS or the hardware. Much of the time, heat issues are caused by software. If you’ve noticed the problem suddenly start, you may want to revoke background app permissions for any apps you’ve recently installed under Settings > General > Background App Refresh.
You may even want to delete any new apps entirely and see if that has any effect, especially if these apps are remaining active in the background all of the time. You can tell an app is active in the background as it will be represented by a bar at the top of the screen when you hit the Home button to minimize it.
- Green bars are calls that are still active in the background, including regular calls and FaceTime.
- Blue bars represent tethered devices or navigation via Apple Maps.
- Red bars indicate an app that is still open in the background, using battery, processing power, possibly even GPS — these are the ones you want to watch.
You can tap on a bar to return to the app or call in question. Many apps that remain active in the background are designed to do so — audio workstations and digital instruments for example — whereas others can simply crash and sit there. To kill an app, double tap the Home button, scroll to the app in question, and flick it toward the top of the screen.
If a rogue app or process isn’t causing the issue, you may want to take more drastic measures. Some users have reported success when restoring their iPhone or iPad in iTunes. To do this, plug your device into a Mac or Windows PC running iTunes, select the device and choose Backup on the Summary tab to create a backup. When complete, choose Restore on the same tab to re-install iOS and wipe the slate clean. You can then restore your device using the backup you made in iTunes when prompted.
Assuming you’ve tried all this, and your problem persists, it might be time to get Apple to take a look. If your device is under warranty (or you have AppleCare) then any repairs will be free of charge. Even if your device isn’t covered, a Genius bar appointment at an Apple retail store won’t cost you anything, and staff won’t charge you unless you authorize repairs.
Finally, third-party chargers from non-certified sources can also cause problems. If you’re going to charge your iPhone, use a first-party charger made by Apple or a third party one that carries the Made for iPhone mark of approval. Uncertified and fraying chargers can damage your devices and have been implicated in house fires.
In Short: Heat is Normal
Your iPhone will get warm to the touch while you use it, and provided it’s not constantly warm for seemingly no reason, there’s little reason to worry. You should always be careful not to leave your devices in the sun, particularly with the screen facing up, as dark colors absorb more heat.
Image credit: iPhone screen repair (Adam Paxson)