Sorority and frat people ----What is a cold dorm?

I was talking over college experiences with someone. I was independent but I remember there was this myth that the frats on campus but moreso the sororities had a specific room in their sorority/frat houses lined with bunks that was simply for sleeping and thus always kept dark at an optimal cool temperature--hence a cold dorm. This was supposed to be seperate from the individual member's shared room with another member.. allowing a person to sleep there is their sleep hours were unconventional or they just needed more quiet, etc. Is this correct? True? I always thought it sounded like such a cool convenience.