I have a split level home built in 1988. On the second floor, I have floor vents and high/low vents in each room. Air is drawn in through the high/low vents and cold air/hot air comes out of the floor vents. My question? What do you call this system? Can I take a wall that has the high/low intake and "cap it" by taking off the top vent??? The intake on the bottom would remain. I would like to turn the wall into a waist high counter. Thanks for any help.