I have a first floor bedroom that was an older 1950's-60 addition to the main circa 1920 house. It has a poured crawl space underneath that is open to the main basement through an old basement window opening approximately 30 inches square. The room is 13'-6" x 11' and has one heat vent in the wall near a corner. Heat source is an older gas forced air system. Currently there is no cold air return in this room. The heat register is about 30' from the furnace. The main duct work is rectangular and has two short 90° branches just before it enters the crawl space under the bedroom and runs parallel to the south wall just a few feet in from the wall. The current register for the room is close to the southwest corner. Should I relocate it in the floor closer to the end of the main duct? And where should a cold air return be located relative to the heat register?
Any thoughts are much appreciated as it is really cold back there.