can i add cold air returns to my second floor without placing ductwork inside the walls? ie using the wall studs on interior wall as ductwork and then connecting to the cold air return ductwork in my basement?
I have three bedrooms upstairs do i need one for each room or will one in the hallway be enough? also I have an old wooden grate return aprox. 2ft by 3ft on the floor of my living room. I'm re-carpeting and want to make this smaller is there a risk of my furnace not performing up to standard if I do so? There are two other cold air returns on my first floor.