I live in a mid 1980's split level and I've been having a huge heating/cooling problem. It's always hot upstairs when heating or cooling. The furnace is mounted very tightly in a closet in the downstairs hallway. There are 2 supply vents going to each bedroom and only two vents going to the large upstairs area. My concern is that they actually used the space under the furnace as the air return, sucking in air from the hallway and both bedrooms. There is no return duct upstairs. Because of the way the joists run there is no way for me to get a return duct upstairs except for running straight up and having a return duct in the middle of the second floor living/dining room area. Is this the best way to go? Suggestions on making the vent less noticeable?