I have a simple layout in my 1200 sq ft 1943 cape cod: 3 returns from the main floor. However, previous owners removed one when finishing the basement & I am getting estimates to have it replaced. There are 2 options for tapping into the return air: either into the main trunk as was originally installed or into one of the existing bedroom returns. Going into the bedroom return is appealing due to the layout of the finished basement, however I'm curious if this is a less efficient way to do it. Does anyone have any input on the furnace's ability to draw air from a room via another room's duct versus it's own dedicated duct?