Don't know much about routers, but I have been rather dismayed by the temperature that some of these cheap units run at.
I've stayed in several folks homes lately, and the amount of kit that sits around almost glowing with warmth, is astonishing. It's bad electronics, and I don't feel it's safe.
A router in Essex, was so hot that you wouldn't want to leave your hand on it. You couldn't have put it against your face! I phoned their son who has several on 24 hours. He said some of those were very hot.
People go out and leave a dozen or so phones, routers, and the like, and a sea of lights on the entertainment area. I suppose it's a testament to modern plastic, that more stuff doesn't go on fire.