What's a 'vapor chamber' in the iPhone 17 Pro and Pro Max?

The flagship iPhones come with a buzzword feature: the vapor chamber. Sounds sci-fi, but it’s really just smart cooling tech.

Picture a flat, sealed metal plate inside the phone, usually copper or aluminium. Inside is a tiny bit of liquid — de-ionised water — and a wick-like structure.

Here’s the trick: when the CPU or GPU gets hot, that liquid absorbs the heat and turns into vapor. The vapor zips across the chamber, spreading the heat evenly.

Then it cools down, turns back into liquid, and dumps the heat out to the phone’s body — like the chassis or back panel.

The condensed liquid is then drawn back to the heat source via capillary action in the wick, repeating the cycle.

The result?

Less overheating, smoother performance, and a cooler hand when you’re gaming, streaming, or pushing the phone to its limits.

It’s like giving your iPhone its own mini air conditioner.

It does not require power, and that's the cool part.

This passive (no moving parts or power required) process allows for efficient, two-dimensional heat spreading over a large surface area, often 0.4mm to 1.0mm thick to fit slim designs.

Unlike simpler graphite sheets or heat pipes, vapor chambers provide more uniform cooling without creating hotspots.

By preventing localised overheating (thermal throttling), it maintains sustained peak performance, reduces the risk of component damage, and keeps the phone's surface temperature comfortable to hold (typically below 42°C even under load), as per Mashable.

It also indirectly extends battery and device lifespan by minimising thermal stress, which can otherwise accelerate degradation. In essence, it acts as a thermal "highway," transforming high heat flux from the processor into a lower, more manageable spread across the device.

Vapor chamber technology evolved from heat pipe principles, which were invented by George Grover at Los Alamos National Laboratory in the 1960s for aerospace applications. 

The planar (flat) vapour chamber variant, suitable for compact electronics like smartphones, was advanced in the 1990s and 2000s by companies such as Thermacore Inc. (now part of AAP) with NASA funding for fuel cell cooling in space missions. 

No single individual is credited with "inventing" the smartphone-specific version, but early commercial adoption came from manufacturers like LG, ASUS, and Samsung in the late 2010s.

It's a collaborative engineering development rather than a patented invention by one person, with ongoing refinements.

In theory, it does.

In lab test, it's shown that by keeping internal temperatures lower, it prevents thermal throttling (which forces the processor to slow down, wasting energy) and reduces heat-related battery drain — high temperatures can accelerate chemical degradation in lithium-ion batteries, shortening lifespan and increasing self-discharge. 

Tests on devices like the Samsung Galaxy S24 and Google Pixel 9 Pro show vapor chambers enable longer sustained performance without excessive power draw, leading to better overall energy efficiency and up to 12°C lower CPU temperatures during use. 

Overheating from poor cooling (not the vapor chamber itself) is what harms batteries, so this tech mitigates that.