Vapor chamber cooling in iPhone 17

Engineers have been working up a sweat trying to prevent devices from overheating

- DAVID CROOKES

HAVE YOU EVER touched your iPhone and flinched because it feels too hot? You’re not alone. This happens more often than you may think, especially if a device is juggling a lot of background processes, or if it’s running particularly demanding apps.

Tasks such as playing games, editing videos, or using Apple Intelligence can put a serious strain on the processors, causing them to generate heat. You may also feel the device heating up when it’s being charged or if you’re in a warm environment, but the situation could be much worse.

Over the years, Apple has developed a series of measures aimed at cooling the iPhone. To ensure the device remains thin, silent, and energy-efficient, they have stopped short of including a fan — an age-old solution that regulates the temperature by drawing in cool air and sending it across hot components — but they do use metal heat sinks, which increase the surface area for heat transfer.

Indeed, the iPhone’s casing is designed not only to look good, but to dissipate heat from the device, transferring it to the surrounding air. The iPhone also includes a nonmetal method to conduct heat — graphite pads in the iPhone 14 and later, while Apple introduced graphene sheets in the iPhone 16 Pro and iPhone 16 Pro Max. These are incredibly thin, single layers of carbon atoms that offer exceptional electrical conductivity.