If the intake is 14" x 8" to the furnace does the vent size have to be bigger? Does it really need a basin to catch air? I'd like to replace the old tin work because i think the air intake is too low and collects dust. I want to continue that same size of 14x8 intake vent and reposition the intake vent inside the stair case higher up from the floor. As it is now it is about 30" x8" which seems overkill to me and is dust trap.