Microsoft tests the Surface Book 3 to avoid ‘hot bag’ heat issues

Microsoft is sweating the details with the Surface Book 3, especially when it comes to thermal issues that users experienced with the Surface Book 2 and the original Surface Book. As the company prepares to launch the Surface Book 3 on May 21, it’s specifically testing the new model for “hot bag” and other heat problems.

Heat issues have affected Microsoft’s Surface devices going back to the Surface Pro 3, but both the original Surface Book and the Surface Pro 4 were plagued by an inability to enter a low-power sleep state. That kept both devices in an an active power state, which consumes lots of power and generates quite a bit of heat as a result. That had two negative effects: greatly diminished battery life, and a surprisingly hot Surface when pulled out of an enclosed, insulated backpack. The issue was significant enough that Surface chief Panos Panay himself announced new firmware that solved the Surface Book power issue several months after its launch.

The Surface Book 2 had its own, separate power problem, where it consumed too much power for the charger to keep up. But in my personal experience, the Surface Book 2 also suffered from the hot-bag problem, which was echoed by other users both on Microsoft’s site and on Reddit. The temperature would climb to levels that were honestly alarming. The Surface Book 2 devices would sometimes refuse to resume operation because the operating temperature exceeded its own thermal limits. 

Microsoft acknowledges that the hot-bag scenario is one “which can destroy your device,” in the words of one Surface executive PCWorld spoke to. Executives responsible for the Microsoft Surface tell PCWorld that part of the Surface Book 3 test suite involves literally putting the Surface Book 3 test units in backpacks and testing for heat buildup. Microsoft also embedded a number of thermal sensors in the Surface Book 3 device itself to prevent this from happening.

While a hot-bag scenario could still occur with the Surface Book 3, the fact that Microsoft is specifically looking out for this issue is good news. Personally, from our own experience with the Surface Book 3 so far, we can report that its cooling is on a par with the Surface Laptop 3’s: excellent, with minimal fan noise or thermal issues. We’ll have a full review soon.