We just bought a 1970's vintage house on acreage. We've noticed that one of the small corner second story rooms is very cold, despite the heat (forced air oil) being on in the house. Closer inspection of the heating grate leads me to believe that instead of heat, this pacticular floor vent is a cold air return. A piece of paper held over it while the furnace is on gets drawn onto the vent, instead of blown upwards. There no other vent in this room. Is it possible this was intentional or a disconnected duct or something else I haven't thougth of? Any ideas? I have a feeling I may be in a "call and HVAC professional" category?
Any help would be appreciated