Here's Why You Should Care About the iPhone 18 Pro's 'Vapor Chambers'
· Lifehacker
During Apple’s big hardware announcement on Wednesday, the company placed a particular emphasis on the vapor chamber in the new iPhone 18 Pro and Pro Max. The glossed-over explanation is that these new vapor chambers can improve performance and reduce heat generation. But how exactly? And what does that mean for the phones you’re planning to buy?
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How vapor chambers work
On a very simple level, vapor chambers work similarly to liquid cooling in other electronics systems like some desktop PCs or server racks. The goal is to carry heat away from the processor to keep it cool, so it can do more work without overheating. A cooler processor is a more efficient processor, which means it runs better.
Except, unlike a PC or server rack, a phone is a tight, compact system. There’s not enough space to heat water and then pump it away to a different location to cool it down. Instead, a vapor chamber is a thin, hollow chamber, typically made of either copper or stainless steel, with a small amount of liquid inside. When the liquid inside heats up, it becomes a gas, which then expands outwards, dispersing the heat throughout the body of your phone, rather than keeping it all close to the processor. As it gets further away from the source of heat, the vapor cools back down and becomes a liquid again.
Since the chamber is sealed, the liquid can’t evaporate and escape, meaning that the fluid can theoretically keep cycling through the chamber indefinitely for the life of the phone. Most manufacturers also pair this with some form of heat sink, like thin sheets of graphite or copper. Or, in the case of the new iPhone 18 Pro, both.
Why vapor chambers matter for smartphones
Keeping your phone cool is a massive problem compared to other electronic devices you might have, simply because they’re so small, yet so powerful. A moderately powered laptop like a MacBook Air can get away with a combination of conductive heat sinks, a metal frame, and low heat-generating processors to stay functional, while high-powered gaming laptops have space to stuff in large, laborious fans.
Your phone, however, needs to fit in your pocket, and a huge chunk of the space inside needs to be devoted to the battery to make sure it lasts long enough to get through the day. Once you account for all the processors, sensors, and antennas that a phone needs, there’s scarcely any space left for heat dissipation. That’s a huge part of why phones generally don’t have as powerful processors as tablets or laptops. Physically, it’s not impossible to fit a high-powered chip in a pocketable device. But it would likely generate so much heat that it would destroy itself without proper heat dissipation, which would make your phone too big for a pocket.
This kind of heat dissipation matters even more if you happen to live in places with warm climates. For example, I live in Texas. Even when driving inside an air-conditioned car, if my phone is in the sunlight, it can start to overheat. When I previously had a Pixel 6 Pro, it would occasionally shut off (taking my navigation with it) simply because it wasn’t in the shade. After upgrading to a Pixel 9 Pro, which does have a vapor chamber, I never noticed this problem—though this is obviously anecdotal.
How to consider vapor chambers when buying a phone
Apple says the iPhone 18 Pro’s vapor chamber has three times the surface area of the previous generation, which theoretically should mean better cooling and, thus, better performance. But does that mean you need to decide what phone to buy based on how big a phone’s vapor chamber is, or whether it has one at all?
Well, yes and no. It turns out that outside the Apple ecosystem, Android phones have been using vapor chambers for years, and you might not have even noticed. The existence of vapor chambers is increasingly becoming standard, so unless you have an old phone that frequently overheats, or you’re looking to buy a phone a few generations behind, you probably don’t need to go out of your way to make sure your phone has one.
And whether bigger is necessarily better is also a bit of a gray area. All other things being equal, yes, a larger vapor chamber will dissipate heat better and keep your phone cooler. But all other things are rarely equal. A larger vapor chamber also means the manufacturer can put a more powerful processor inside and achieve the same thermal balance. So, a phone could theoretically be equally likely to overheat, but do more before it does.
Figuring out the right balance between processing power and heat dissipation is the kind of thing best left to the engineers and dedicated hobbyists. But there are a couple of things the average person can take away from this. First, if you live in a warm climate, better heat dissipation is always going to be better. Your phone isn’t running at full power all day, but the Texas sun is. So, if you’re worried about your environment causing overheating problems, check phone reviews for how well it handles heat. More importantly, consider the power needs you have for your device before you buy. If you just use your phone to scroll TikTok and reply to emails, you probably don’t need an overpowered processor, but if you plan to edit 4K videos or play graphically intense mobile games, then better thermal regulation could do you some good.