[Brian F]

I'm in the process of finishing my basement and would like to install a return air duct. where I would like to put the air duct there is a return going to a room upstairs. Can I use the same hole that is cut in that the main duct and use it for the return for my basement also?

 

[beenthere]

Shouldn't, as it can cause the return of the upstairs return not to pull as much air.