When I have the AC or fans on in my car and I hit the brakes hard, the air coming out of the vents actually turns hot. Is this something to worry about? It only happens when I brake much harder than usual.

 

can anyone atleast confirm their car does the same XD then I'll be more at peace with it

 

Just a wild guess, but I think the flaps that control the hot/cold air distribution are wimpy-vacuum operated. Maybe when you brake very hard, the braking force overcomes the wimpy-vacuum force & the flap moves from cold to hot. I expect it's OK once you've stopped.
Just a guess!

 

You're right, it goes back to normal when I'm at a complete stop. In that case, as long as it doesn't affect the drivability, I guess I don't care. :D