I am remodeling a rental that was installed a Lennox 92% efficient furnace in over a year ago. The installers put a ugly 6"x24" floor grate in the corner of the living room floor above the newly installed furnace. While remodeling I want to get rid of the floor grate by placing a 1/2 wall above the floor grate area(which will also provide privacy to the master bedroom and bathroom doors from the front room) and install a 6"x24" vent within the half wall. Does a cold air return floor grate measuring 6"x24" floor and a 6"x24" wall vent bring in the same amount of air? Or does the furnace need to work a bit harder for the air?The half wall would be made of 2x4's and sheetrock.

you wall has to be 6 inchs thick... open... so the wall opening should be 6x24

Okay. Are you a HVAC specialist? The open 1/2 wall is already installed. If I put two 6x24 wall vents on each side of the half wall would that be any better for circulation (instead of just one)? Is the loss of 2 inches a super big deal?

yes.. that may be OK... it has to be the same cubit inchs or more... 12 x 6 = 72 cub in

it nees to be about 72 cu in through the inside of the wall... it won't work if u just going through a 2 x 4 x 14 1/2 in wall that's only about 50 cu in... richard