Why is the red room the punishment location, and why is it not hot, as the color red would suggest it to be?

The book says that the red-room is supposed to symbolize a hell-room. It doesn't have hot flames, but it instead was chill, so it was terrifying to have to go in it. Also, as the name suggests, the contents inside the room are red. This is the punishment location as it is remote from the nursery and kitchens, so it was terrifyingly quiet being in there alone. It is also called the red room, as it represents hell, and Mr. Reed died in this chamber, so his body stays in the room, and some believe that he haunts the imbeciles who end up in there.