You can disapate heat into the metal chassis without a fan, and if your CPU only generates a few watts, even at 100% this doesn’t cause it to overheat. This has been done with desktops that are.much more powerful, but it’s also been done on the new M2 MacBook air, because the m2 CPU is quite efficient. It doesn’t overheat because the case passively dissapates heat fast enough. It’s also not a performance laptop.