Adding return duct on second floor?
We have a bungalow, built in 1954 that probably had a gravity furnace to start. It’s had an addition, so upstairs is now three bedrooms, a bathroom, 2 large closets. There are 5 forced air vents upstairs and no returns. You can feel the air rushing down the stairs to the first floor, where it mixes with the 1st floor air and then finds the three return ducts on the first floor.
I’m removing an unused chimney later this week and that will open up a space from almost the top of the stairs, on the side wall, all the way to the basement.
I’m trying to decide if adding a return vent there makes sense. A quick internet search says no, that as long as the air has a way down it’s fine and that more supply is more effective. I would have thought that a straight path for that cold air to the furnace without cooling the first floor first would be preferred.
Opinions and reasoning welcome.
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