Our unfinished basement has no air returns to the furnace. I've read that one should be installed as close to the floor as possible. I've also read that none should be installed in the same room as the furnace (carbon monoxide concerns I believe). I would like to install one to alleviate the coldness when the AC is on. Any thoughts? If they are okay to install, what would be the best method? Is putting a vent on the side of the ductwork going into the furnace advisable?
Answer:
old air falls and that tells you that the return air grill should be as close to the floor as possible. You can tap into the cold air plenum anywhere along its length to make sure you have a return air duct in every room down there. I try, as much as I can, to use dividing wall cavities so one duct actually services two rooms.
