Sometimes people will ask me, “Hadley, does your apartment have air conditioning?” Even my mom, year after year will ask me, “Why don’t you put in an air conditioner?” I don’t have air conditioning at my apartment. Mostly because I have casement windows, and I don’t want to use one of those bulky indoor units. Besides, it’s Vermont, and I live up in the mountains. I don’t think I’ve ever even seen it hit 90 at my apartment since moving there. I can tough it out for the few days of the year where it’s oppressively hot. Usually I just remind myself that in 6 months, it’ll be -10F again.
But when I’m sitting at home on my MacBook Air, I’m usually on my couch all curled up. You’d think it would be hot, but with a fan on me, and the window open, it’s not bad. One thing I have noticed though is that my Mac does get pretty hot. Like so hot I can feel it through the keyboard as I’m typing. It’s kind of uncomfortable.
It’s not overheating though. I use iStat Menus to monitor my machine. I keep the CPU temperature displayed in the menu bar at all times. Even when I can feel the heat through the keyboard, the CPU temperature is hovering somewhere between 70C and 80C which is perfect for Intel CPUs. What’s going on here?
Because the MacBook cases are made of aluminum, they use that to passively dissipate heat in addition to active cooling by fans. The large surface area of the aluminum case allows the machine to dump heat to it, which is then transferred to the ambient environment. In my case, the “ambient environment” is my hands. The new 12-inch MacBooks don’t even have any fans at all. They’re cooled completely passively.
So are you doomed to hot fingers and a hot machine when the weather heats up? Not if you have a Mac with active cooling. iStat Menus doesn’t just monitor your system, it also has settings to control the fans. Normally the fans on your Mac run as slowly as possible to conserve power and reduce noise. They only spin up to max speed if they absolutely have to because the machine is working really hard. If you override that control and lock them into max speed with software like iStat Menus, they will cool your machine down further than normal. When I have the fan on my MacBook Air at max RPM, the CPU temperature drops to the mid 40s C. The case gets substantially cooler, and I’m comfortable again!
Of course, the trade off is that doing this will make your machine pretty loud. You can also choose to set the fans to never fall below a certain RPM. This can help compromise between noise and coolness. Stay cool!