I live in a three bedroom bungalow with a fairly new furnace installed since moving in. I have what appears to be three cold air returns: one in the front hallway close to the livingroom, one in a bedroom upstairs and the other is in the basement hallway. The house originally had three bedrooms but the people before me converted two bedrooms into one massive room. I am in the process of converting the rooms back to two seperate rooms. However the room has three floor vents. Two are located under the windows near the outside wall. One floor vent appears to be directly in the way of where the wall needs to be located. It looks like the people cut through the duct a whole about 10.5 inches by 8.5 inches and made a seperate cut through the subfloor several inches away from the cut duct work. there is no duct work to connect the holes. There was a normal unstable floor vent covering the hole in the subfloor. When the furnace is on the air from this vent appears to be cold blowing air. Originally I was going to cover it all up and build the wall thinking they cut the hole to add more warm to the room. What should I do?