Cold Air Return
DEAR TIM: We live in a Cape Cod style house that was built in the early 1960's. The problem is that in the summer the basement is cold, the main floor is comfortable, and the upstairs is hot. In the winter the reverse is true. The basement is hot, main floor comfortable, and the upstairs is cold. Every supply vent is open on the upstairs, and closed in the basement. There is no cold air return from the upstairs, so from what I've read, that seems to be my problem. I would like to know where to install return ducts. I understand what you said about them being near the ceiling to bring the hot air back down in the summer time. But in the winter, would that not also return the hot air needed to heat the room. Should there be two sets, one for summer near the ceiling, and one in winter, near the floor to get rid of the cold air? Tim Schoell, Omaha, NE
DEAR TIM: Ideally you want to have cold air return registers in every room. These should be located at the top of the wall on an interior wall. The supply registers should always be on an exterior wall preferably under a window or near a door.
You don't need two sets of cold air return vents. The reason is simple. The supply vents should be in the floor and the cold air return grilles are high on wall. If you could see the air come out of the floor registers, you'd see it be pulled across and up through the room. Because your body is in this path way, you get the benefit of either hot air or cold air being drawn across your skin providing you comfort.
If you can't easily install a true cold air duct back to the furnace from each room, you can sometimes fake it. You can install a cold air return register above the door from each room that connects to the hallway. The air flows through these openings from each room. The air flows across the ceiling in the hallway towards a larger cold air return that does extend to the basement furnace.
You do this and I guarantee you that the second floor is going to be much more comfortable year round.