joist to joist return connection

[Irishmist]

fair enough. Thanks Doc. I would think the problem you refer to would not be as much of a problem unless you were attemping to pull your total amount of return through a single space. This return may only account for approximately 1/5 of the total air return.

[jrbenny]

90° adjustable elbow is 10 equivalent feet. So, the jumper would be 41 or 42 equivalent feet presuming you use sheet metal pipe between the elbows.